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[Emacs-diffs] Changes to processes.texi
|
From: |
Glenn Morris |
|
Subject: |
[Emacs-diffs] Changes to processes.texi |
|
Date: |
Thu, 06 Sep 2007 04:13:56 +0000 |
CVSROOT: /sources/emacs
Module name: emacs
Changes by: Glenn Morris <gm> 07/09/06 04:13:55
Index: processes.texi
===================================================================
RCS file: processes.texi
diff -N processes.texi
--- processes.texi 16 Aug 2007 02:22:40 -0000 1.106
+++ /dev/null 1 Jan 1970 00:00:00 -0000
@@ -1,2561 +0,0 @@
address@hidden -*-texinfo-*-
address@hidden This is part of the GNU Emacs Lisp Reference Manual.
address@hidden Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1998, 1999,
2001,
address@hidden 2002, 2003, 2004, 2005, 2006, 2007 Free Software Foundation,
Inc.
address@hidden See the file elisp.texi for copying conditions.
address@hidden ../info/processes
address@hidden Processes, Display, Abbrevs, Top
address@hidden Processes
address@hidden child process
address@hidden parent process
address@hidden subprocess
address@hidden process
-
- In the terminology of operating systems, a @dfn{process} is a space in
-which a program can execute. Emacs runs in a process. Emacs Lisp
-programs can invoke other programs in processes of their own. These are
-called @dfn{subprocesses} or @dfn{child processes} of the Emacs process,
-which is their @dfn{parent process}.
-
- A subprocess of Emacs may be @dfn{synchronous} or @dfn{asynchronous},
-depending on how it is created. When you create a synchronous
-subprocess, the Lisp program waits for the subprocess to terminate
-before continuing execution. When you create an asynchronous
-subprocess, it can run in parallel with the Lisp program. This kind of
-subprocess is represented within Emacs by a Lisp object which is also
-called a ``process.'' Lisp programs can use this object to communicate
-with the subprocess or to control it. For example, you can send
-signals, obtain status information, receive output from the process, or
-send input to it.
-
address@hidden processp object
-This function returns @code{t} if @var{object} is a process,
address@hidden otherwise.
address@hidden defun
-
address@hidden
-* Subprocess Creation:: Functions that start subprocesses.
-* Shell Arguments:: Quoting an argument to pass it to a shell.
-* Synchronous Processes:: Details of using synchronous subprocesses.
-* Asynchronous Processes:: Starting up an asynchronous subprocess.
-* Deleting Processes:: Eliminating an asynchronous subprocess.
-* Process Information:: Accessing run-status and other attributes.
-* Input to Processes:: Sending input to an asynchronous subprocess.
-* Signals to Processes:: Stopping, continuing or interrupting
- an asynchronous subprocess.
-* Output from Processes:: Collecting output from an asynchronous subprocess.
-* Sentinels:: Sentinels run when process run-status changes.
-* Query Before Exit:: Whether to query if exiting will kill a process.
-* Transaction Queues:: Transaction-based communication with subprocesses.
-* Network:: Opening network connections.
-* Network Servers:: Network servers let Emacs accept net connections.
-* Datagrams:: UDP network connections.
-* Low-Level Network:: Lower-level but more general function
- to create connections and servers.
-* Misc Network:: Additional relevant functions for network
connections.
-* Byte Packing:: Using bindat to pack and unpack binary data.
address@hidden menu
-
address@hidden Subprocess Creation
address@hidden Functions that Create Subprocesses
-
- There are three functions that create a new subprocess in which to run
-a program. One of them, @code{start-process}, creates an asynchronous
-process and returns a process object (@pxref{Asynchronous Processes}).
-The other two, @code{call-process} and @code{call-process-region},
-create a synchronous process and do not return a process object
-(@pxref{Synchronous Processes}).
-
- Synchronous and asynchronous processes are explained in the following
-sections. Since the three functions are all called in a similar
-fashion, their common arguments are described here.
-
address@hidden execute program
address@hidden @code{PATH} environment variable
address@hidden @code{HOME} environment variable
- In all cases, the function's @var{program} argument specifies the
-program to be run. An error is signaled if the file is not found or
-cannot be executed. If the file name is relative, the variable
address@hidden contains a list of directories to search. Emacs
-initializes @code{exec-path} when it starts up, based on the value of
-the environment variable @code{PATH}. The standard file name
-constructs, @samp{~}, @samp{.}, and @samp{..}, are interpreted as
-usual in @code{exec-path}, but environment variable substitutions
-(@samp{$HOME}, etc.) are not recognized; use
address@hidden to perform them (@pxref{File Name
-Expansion}). @code{nil} in this list refers to
address@hidden
-
- Executing a program can also try adding suffixes to the specified
-name:
-
address@hidden exec-suffixes
-This variable is a list of suffixes (strings) to try adding to the
-specified program file name. The list should include @code{""} if you
-want the name to be tried exactly as specified. The default value is
-system-dependent.
address@hidden defvar
-
- @strong{Please note:} The argument @var{program} contains only the
-name of the program; it may not contain any command-line arguments. You
-must use @var{args} to provide those.
-
- Each of the subprocess-creating functions has a @var{buffer-or-name}
-argument which specifies where the standard output from the program will
-go. It should be a buffer or a buffer name; if it is a buffer name,
-that will create the buffer if it does not already exist. It can also
-be @code{nil}, which says to discard the output unless a filter function
-handles it. (@xref{Filter Functions}, and @ref{Read and Print}.)
-Normally, you should avoid having multiple processes send output to the
-same buffer because their output would be intermixed randomly.
-
address@hidden program arguments
- All three of the subprocess-creating functions have a @code{&rest}
-argument, @var{args}. The @var{args} must all be strings, and they are
-supplied to @var{program} as separate command line arguments. Wildcard
-characters and other shell constructs have no special meanings in these
-strings, since the strings are passed directly to the specified program.
-
- The subprocess gets its current directory from the value of
address@hidden (@pxref{File Name Expansion}).
-
address@hidden environment variables, subprocesses
- The subprocess inherits its environment from Emacs, but you can
-specify overrides for it with @code{process-environment}. @xref{System
-Environment}.
-
address@hidden exec-directory
address@hidden movemail
-The value of this variable is a string, the name of a directory that
-contains programs that come with GNU Emacs, programs intended for Emacs
-to invoke. The program @code{movemail} is an example of such a program;
-Rmail uses it to fetch new mail from an inbox.
address@hidden defvar
-
address@hidden exec-path
-The value of this variable is a list of directories to search for
-programs to run in subprocesses. Each element is either the name of a
-directory (i.e., a string), or @code{nil}, which stands for the default
-directory (which is the value of @code{default-directory}).
address@hidden program directories
-
-The value of @code{exec-path} is used by @code{call-process} and
address@hidden when the @var{program} argument is not an absolute
-file name.
address@hidden defopt
-
address@hidden Shell Arguments
address@hidden Shell Arguments
address@hidden arguments for shell commands
address@hidden shell command arguments
-
- Lisp programs sometimes need to run a shell and give it a command
-that contains file names that were specified by the user. These
-programs ought to be able to support any valid file name. But the shell
-gives special treatment to certain characters, and if these characters
-occur in the file name, they will confuse the shell. To handle these
-characters, use the function @code{shell-quote-argument}:
-
address@hidden shell-quote-argument argument
-This function returns a string which represents, in shell syntax,
-an argument whose actual contents are @var{argument}. It should
-work reliably to concatenate the return value into a shell command
-and then pass it to a shell for execution.
-
-Precisely what this function does depends on your operating system. The
-function is designed to work with the syntax of your system's standard
-shell; if you use an unusual shell, you will need to redefine this
-function.
-
address@hidden
-;; @r{This example shows the behavior on GNU and Unix systems.}
-(shell-quote-argument "foo > bar")
- @result{} "foo\\ \\>\\ bar"
-
-;; @r{This example shows the behavior on MS-DOS and MS-Windows.}
-(shell-quote-argument "foo > bar")
- @result{} "\"foo > bar\""
address@hidden example
-
-Here's an example of using @code{shell-quote-argument} to construct
-a shell command:
-
address@hidden
-(concat "diff -c "
- (shell-quote-argument oldfile)
- " "
- (shell-quote-argument newfile))
address@hidden example
address@hidden defun
-
address@hidden Synchronous Processes
address@hidden Creating a Synchronous Process
address@hidden synchronous subprocess
-
- After a @dfn{synchronous process} is created, Emacs waits for the
-process to terminate before continuing. Starting Dired on GNU or
address@hidden other systems, Emacs uses a Lisp emulation of
address@hidden; see @ref{Contents of Directories}.} is an example of this: it
-runs @code{ls} in a synchronous process, then modifies the output
-slightly. Because the process is synchronous, the entire directory
-listing arrives in the buffer before Emacs tries to do anything with it.
-
- While Emacs waits for the synchronous subprocess to terminate, the
-user can quit by typing @kbd{C-g}. The first @kbd{C-g} tries to kill
-the subprocess with a @code{SIGINT} signal; but it waits until the
-subprocess actually terminates before quitting. If during that time the
-user types another @kbd{C-g}, that kills the subprocess instantly with
address@hidden and quits immediately (except on MS-DOS, where killing
-other processes doesn't work). @xref{Quitting}.
-
- The synchronous subprocess functions return an indication of how the
-process terminated.
-
- The output from a synchronous subprocess is generally decoded using a
-coding system, much like text read from a file. The input sent to a
-subprocess by @code{call-process-region} is encoded using a coding
-system, much like text written into a file. @xref{Coding Systems}.
-
address@hidden call-process program &optional infile destination display &rest
args
-This function calls @var{program} in a separate process and waits for
-it to finish.
-
-The standard input for the process comes from file @var{infile} if
address@hidden is not @code{nil}, and from the null device otherwise.
-The argument @var{destination} says where to put the process output.
-Here are the possibilities:
-
address@hidden @asis
address@hidden a buffer
-Insert the output in that buffer, before point. This includes both the
-standard output stream and the standard error stream of the process.
-
address@hidden a string
-Insert the output in a buffer with that name, before point.
-
address@hidden @code{t}
-Insert the output in the current buffer, before point.
-
address@hidden @code{nil}
-Discard the output.
-
address@hidden 0
-Discard the output, and return @code{nil} immediately without waiting
-for the subprocess to finish.
-
-In this case, the process is not truly synchronous, since it can run in
-parallel with Emacs; but you can think of it as synchronous in that
-Emacs is essentially finished with the subprocess as soon as this
-function returns.
-
-MS-DOS doesn't support asynchronous subprocesses, so this option doesn't
-work there.
-
address@hidden @code{(@var{real-destination} @var{error-destination})}
-Keep the standard output stream separate from the standard error stream;
-deal with the ordinary output as specified by @var{real-destination},
-and dispose of the error output according to @var{error-destination}.
-If @var{error-destination} is @code{nil}, that means to discard the
-error output, @code{t} means mix it with the ordinary output, and a
-string specifies a file name to redirect error output into.
-
-You can't directly specify a buffer to put the error output in; that is
-too difficult to implement. But you can achieve this result by sending
-the error output to a temporary file and then inserting the file into a
-buffer.
address@hidden table
-
-If @var{display} is address@hidden, then @code{call-process} redisplays
-the buffer as output is inserted. (However, if the coding system chosen
-for decoding output is @code{undecided}, meaning deduce the encoding
-from the actual data, then redisplay sometimes cannot continue once
address@hidden characters are encountered. There are fundamental
-reasons why it is hard to fix this; see @ref{Output from Processes}.)
-
-Otherwise the function @code{call-process} does no redisplay, and the
-results become visible on the screen only when Emacs redisplays that
-buffer in the normal course of events.
-
-The remaining arguments, @var{args}, are strings that specify command
-line arguments for the program.
-
-The value returned by @code{call-process} (unless you told it not to
-wait) indicates the reason for process termination. A number gives the
-exit status of the subprocess; 0 means success, and any other value
-means failure. If the process terminated with a signal,
address@hidden returns a string describing the signal.
-
-In the examples below, the buffer @samp{foo} is current.
-
address@hidden
address@hidden
-(call-process "pwd" nil t)
- @result{} 0
-
----------- Buffer: foo ----------
-/usr/user/lewis/manual
----------- Buffer: foo ----------
address@hidden group
-
address@hidden
-(call-process "grep" nil "bar" nil "lewis" "/etc/passwd")
- @result{} 0
-
----------- Buffer: bar ----------
-lewis:5LTsHm66CSWKg:398:21:Bil Lewis:/user/lewis:/bin/csh
-
----------- Buffer: bar ----------
address@hidden group
address@hidden smallexample
-
-Here is a good example of the use of @code{call-process}, which used to
-be found in the definition of @code{insert-directory}:
-
address@hidden
address@hidden
-(call-process insert-directory-program nil t nil @var{switches}
- (if full-directory-p
- (concat (file-name-as-directory file) ".")
- file))
address@hidden group
address@hidden smallexample
address@hidden defun
-
address@hidden process-file program &optional infile buffer display &rest args
-This function processes files synchronously in a separate process. It
-is similar to @code{call-process} but may invoke a file handler based
-on the value of the variable @code{default-directory}. The current
-working directory of the subprocess is @code{default-directory}.
-
-The arguments are handled in almost the same way as for
address@hidden, with the following differences:
-
-Some file handlers may not support all combinations and forms of the
-arguments @var{infile}, @var{buffer}, and @var{display}. For example,
-some file handlers might behave as if @var{display} were @code{nil},
-regardless of the value actually passed. As another example, some
-file handlers might not support separating standard output and error
-output by way of the @var{buffer} argument.
-
-If a file handler is invoked, it determines the program to run based
-on the first argument @var{program}. For instance, consider that a
-handler for remote files is invoked. Then the path that is used for
-searching the program might be different than @code{exec-path}.
-
-The second argument @var{infile} may invoke a file handler. The file
-handler could be different from the handler chosen for the
address@hidden function itself. (For example,
address@hidden could be on a remote host, whereas
address@hidden is on another remote host. Or @code{default-directory}
-could be non-special, whereas @var{infile} is on a remote host.)
-
-If @var{buffer} is a list of the form @code{(@var{real-destination}
address@hidden)}, and @var{error-destination} names a file,
-then the same remarks as for @var{infile} apply.
-
-The remaining arguments (@var{args}) will be passed to the process
-verbatim. Emacs is not involved in processing file names that are
-present in @var{args}. To avoid confusion, it may be best to avoid
-absolute file names in @var{args}, but rather to specify all file
-names as relative to @code{default-directory}. The function
address@hidden is useful for constructing such relative
-file names.
address@hidden defun
-
address@hidden call-process-region start end program &optional delete
destination display &rest args
-This function sends the text from @var{start} to @var{end} as
-standard input to a process running @var{program}. It deletes the text
-sent if @var{delete} is address@hidden; this is useful when
address@hidden is @code{t}, to insert the output in the current
-buffer in place of the input.
-
-The arguments @var{destination} and @var{display} control what to do
-with the output from the subprocess, and whether to update the display
-as it comes in. For details, see the description of
address@hidden, above. If @var{destination} is the integer 0,
address@hidden discards the output and returns @code{nil}
-immediately, without waiting for the subprocess to finish (this only
-works if asynchronous subprocesses are supported).
-
-The remaining arguments, @var{args}, are strings that specify command
-line arguments for the program.
-
-The return value of @code{call-process-region} is just like that of
address@hidden: @code{nil} if you told it to return without
-waiting; otherwise, a number or string which indicates how the
-subprocess terminated.
-
-In the following example, we use @code{call-process-region} to run the
address@hidden utility, with standard input being the first five characters
-in buffer @samp{foo} (the word @samp{input}). @code{cat} copies its
-standard input into its standard output. Since the argument
address@hidden is @code{t}, this output is inserted in the current
-buffer.
-
address@hidden
address@hidden
----------- Buffer: foo ----------
address@hidden
----------- Buffer: foo ----------
address@hidden group
-
address@hidden
-(call-process-region 1 6 "cat" nil t)
- @result{} 0
-
----------- Buffer: foo ----------
address@hidden
----------- Buffer: foo ----------
address@hidden group
address@hidden smallexample
-
- The @code{shell-command-on-region} command uses
address@hidden like this:
-
address@hidden
address@hidden
-(call-process-region
- start end
- shell-file-name ; @r{Name of program.}
- nil ; @r{Do not delete region.}
- buffer ; @r{Send output to @code{buffer}.}
- nil ; @r{No redisplay during output.}
- "-c" command) ; @r{Arguments for the shell.}
address@hidden group
address@hidden smallexample
address@hidden defun
-
address@hidden call-process-shell-command command &optional infile destination
display &rest args
-This function executes the shell command @var{command} synchronously
-in a separate process. The final arguments @var{args} are additional
-arguments to add at the end of @var{command}. The other arguments
-are handled as in @code{call-process}.
address@hidden defun
-
address@hidden process-file-shell-command command &optional infile destination
display &rest args
-This function is like @code{call-process-shell-command}, but uses
address@hidden internally. Depending on @code{default-directory},
address@hidden can be executed also on remote hosts.
address@hidden defun
-
address@hidden shell-command-to-string command
-This function executes @var{command} (a string) as a shell command,
-then returns the command's output as a string.
address@hidden defun
-
address@hidden Asynchronous Processes
address@hidden Creating an Asynchronous Process
address@hidden asynchronous subprocess
-
- After an @dfn{asynchronous process} is created, Emacs and the subprocess
-both continue running immediately. The process thereafter runs
-in parallel with Emacs, and the two can communicate with each other
-using the functions described in the following sections. However,
-communication is only partially asynchronous: Emacs sends data to the
-process only when certain functions are called, and Emacs accepts data
-from the process only when Emacs is waiting for input or for a time
-delay.
-
- Here we describe how to create an asynchronous process.
-
address@hidden start-process name buffer-or-name program &rest args
-This function creates a new asynchronous subprocess and starts the
-program @var{program} running in it. It returns a process object that
-stands for the new subprocess in Lisp. The argument @var{name}
-specifies the name for the process object; if a process with this name
-already exists, then @var{name} is modified (by appending @samp{<1>},
-etc.) to be unique. The buffer @var{buffer-or-name} is the buffer to
-associate with the process.
-
-The remaining arguments, @var{args}, are strings that specify command
-line arguments for the program.
-
-In the example below, the first process is started and runs (rather,
-sleeps) for 100 seconds. Meanwhile, the second process is started, and
-given the name @samp{my-process<1>} for the sake of uniqueness. It
-inserts the directory listing at the end of the buffer @samp{foo},
-before the first process finishes. Then it finishes, and a message to
-that effect is inserted in the buffer. Much later, the first process
-finishes, and another message is inserted in the buffer for it.
-
address@hidden
address@hidden
-(start-process "my-process" "foo" "sleep" "100")
- @result{} #<process my-process>
address@hidden group
-
address@hidden
-(start-process "my-process" "foo" "ls" "-l" "/user/lewis/bin")
- @result{} #<process my-process<1>>
-
----------- Buffer: foo ----------
-total 2
-lrwxrwxrwx 1 lewis 14 Jul 22 10:12 gnuemacs --> /emacs
--rwxrwxrwx 1 lewis 19 Jul 30 21:02 lemon
-
-Process my-process<1> finished
-
-Process my-process finished
----------- Buffer: foo ----------
address@hidden group
address@hidden smallexample
address@hidden defun
-
address@hidden start-file-process name buffer-or-name program &rest args
-Like @code{start-process}, this function starts a new asynchronous
-subprocess running @var{program} in it, and returns its process
-object---when @code{default-directory} is not a magic file name.
-
-If @code{default-directory} is magic, the function invokes its file
-handler instead. This handler ought to run @var{program}, perhaps on
-the local host, perhaps on a remote host that corresponds to
address@hidden In the latter case, the local part of
address@hidden becomes the working directory of the process.
-
-This function does not try to invoke file name handlers for
address@hidden or for the @var{program-args}.
-
-Depending on the implementation of the file handler, it might not be
-possible to apply @code{process-filter} or @code{process-sentinel} to
-the resulting process object (@pxref{Filter Functions}, @pxref{Sentinels}).
-
-Some file handlers may not support @code{start-file-process} (for
-example @code{ange-ftp-hook-function}). In such cases, the function
-does nothing and returns @code{nil}.
address@hidden defun
-
address@hidden start-process-shell-command name buffer-or-name command &rest
command-args
-This function is like @code{start-process} except that it uses a shell
-to execute the specified command. The argument @var{command} is a shell
-command name, and @var{command-args} are the arguments for the shell
-command. The variable @code{shell-file-name} specifies which shell to
-use.
-
-The point of running a program through the shell, rather than directly
-with @code{start-process}, is so that you can employ shell features such
-as wildcards in the arguments. It follows that if you include an
-arbitrary user-specified arguments in the command, you should quote it
-with @code{shell-quote-argument} first, so that any special shell
-characters do @emph{not} have their special shell meanings. @xref{Shell
-Arguments}.
address@hidden defun
-
address@hidden start-file-process-shell-command name buffer-or-name command
&rest command-args
-This function is like @code{start-process-shell-command}, but uses
address@hidden internally. By this, @var{command} can be
-executed also on remote hosts, depending on @code{default-directory}.
address@hidden defun
-
address@hidden process-connection-type
address@hidden pipes
address@hidden @acronym{PTY}s
-This variable controls the type of device used to communicate with
-asynchronous subprocesses. If it is address@hidden, then @acronym{PTY}s are
-used, when available. Otherwise, pipes are used.
-
address@hidden are usually preferable for processes visible to the user, as
-in Shell mode, because they allow job control (@kbd{C-c}, @kbd{C-z},
-etc.) to work between the process and its children, whereas pipes do
-not. For subprocesses used for internal purposes by programs, it is
-often better to use a pipe, because they are more efficient. In
-addition, the total number of @acronym{PTY}s is limited on many systems and
-it is good not to waste them.
-
-The value of @code{process-connection-type} takes effect when
address@hidden is called. So you can specify how to communicate
-with one subprocess by binding the variable around the call to
address@hidden
-
address@hidden
address@hidden
-(let ((process-connection-type nil)) ; @r{Use a pipe.}
- (start-process @dots{}))
address@hidden group
address@hidden smallexample
-
-To determine whether a given subprocess actually got a pipe or a
address@hidden, use the function @code{process-tty-name} (@pxref{Process
-Information}).
address@hidden defvar
-
address@hidden Deleting Processes
address@hidden Deleting Processes
address@hidden deleting processes
-
- @dfn{Deleting a process} disconnects Emacs immediately from the
-subprocess. Processes are deleted automatically after they terminate,
-but not necessarily right away. You can delete a process explicitly
-at any time. If you delete a terminated process explicitly before it
-is deleted automatically, no harm results. Deleting a running
-process sends a signal to terminate it (and its child processes if
-any), and calls the process sentinel if it has one. @xref{Sentinels}.
-
- When a process is deleted, the process object itself continues to
-exist as long as other Lisp objects point to it. All the Lisp
-primitives that work on process objects accept deleted processes, but
-those that do I/O or send signals will report an error. The process
-mark continues to point to the same place as before, usually into a
-buffer where output from the process was being inserted.
-
address@hidden delete-exited-processes
-This variable controls automatic deletion of processes that have
-terminated (due to calling @code{exit} or to a signal). If it is
address@hidden, then they continue to exist until the user runs
address@hidden Otherwise, they are deleted immediately after
-they exit.
address@hidden defopt
-
address@hidden delete-process process
-This function deletes a process, killing it with a @code{SIGKILL}
-signal. The argument may be a process, the name of a process, a
-buffer, or the name of a buffer. (A buffer or buffer-name stands for
-the process that @code{get-buffer-process} returns.) Calling
address@hidden on a running process terminates it, updates the
-process status, and runs the sentinel (if any) immediately. If the
-process has already terminated, calling @code{delete-process} has no
-effect on its status, or on the running of its sentinel (which will
-happen sooner or later).
-
address@hidden
address@hidden
-(delete-process "*shell*")
- @result{} nil
address@hidden group
address@hidden smallexample
address@hidden defun
-
address@hidden Process Information
address@hidden Process Information
-
- Several functions return information about processes.
address@hidden is provided for interactive use.
-
address@hidden Command list-processes &optional query-only
-This command displays a listing of all living processes. In addition,
-it finally deletes any process whose status was @samp{Exited} or
address@hidden It returns @code{nil}.
-
-If @var{query-only} is address@hidden then it lists only processes
-whose query flag is address@hidden @xref{Query Before Exit}.
address@hidden deffn
-
address@hidden process-list
-This function returns a list of all processes that have not been deleted.
-
address@hidden
address@hidden
-(process-list)
- @result{} (#<process display-time> #<process shell>)
address@hidden group
address@hidden smallexample
address@hidden defun
-
address@hidden get-process name
-This function returns the process named @var{name}, or @code{nil} if
-there is none. An error is signaled if @var{name} is not a string.
-
address@hidden
address@hidden
-(get-process "shell")
- @result{} #<process shell>
address@hidden group
address@hidden smallexample
address@hidden defun
-
address@hidden process-command process
-This function returns the command that was executed to start
address@hidden This is a list of strings, the first string being the
-program executed and the rest of the strings being the arguments that
-were given to the program.
-
address@hidden
address@hidden
-(process-command (get-process "shell"))
- @result{} ("/bin/csh" "-i")
address@hidden group
address@hidden smallexample
address@hidden defun
-
address@hidden process-id process
-This function returns the @acronym{PID} of @var{process}. This is an
-integer that distinguishes the process @var{process} from all other
-processes running on the same computer at the current time. The
address@hidden of a process is chosen by the operating system kernel when the
-process is started and remains constant as long as the process exists.
address@hidden defun
-
address@hidden process-name process
-This function returns the name of @var{process}.
address@hidden defun
-
address@hidden process-status process-name
-This function returns the status of @var{process-name} as a symbol.
-The argument @var{process-name} must be a process, a buffer, a
-process name (string) or a buffer name (string).
-
-The possible values for an actual subprocess are:
-
address@hidden @code
address@hidden run
-for a process that is running.
address@hidden stop
-for a process that is stopped but continuable.
address@hidden exit
-for a process that has exited.
address@hidden signal
-for a process that has received a fatal signal.
address@hidden open
-for a network connection that is open.
address@hidden closed
-for a network connection that is closed. Once a connection
-is closed, you cannot reopen it, though you might be able to open
-a new connection to the same place.
address@hidden connect
-for a non-blocking connection that is waiting to complete.
address@hidden failed
-for a non-blocking connection that has failed to complete.
address@hidden listen
-for a network server that is listening.
address@hidden nil
-if @var{process-name} is not the name of an existing process.
address@hidden table
-
address@hidden
address@hidden
-(process-status "shell")
- @result{} run
address@hidden group
address@hidden
-(process-status (get-buffer "*shell*"))
- @result{} run
address@hidden group
address@hidden
-x
- @result{} #<process xx<1>>
-(process-status x)
- @result{} exit
address@hidden group
address@hidden smallexample
-
-For a network connection, @code{process-status} returns one of the symbols
address@hidden or @code{closed}. The latter means that the other side
-closed the connection, or Emacs did @code{delete-process}.
address@hidden defun
-
address@hidden process-exit-status process
-This function returns the exit status of @var{process} or the signal
-number that killed it. (Use the result of @code{process-status} to
-determine which of those it is.) If @var{process} has not yet
-terminated, the value is 0.
address@hidden defun
-
address@hidden process-tty-name process
-This function returns the terminal name that @var{process} is using for
-its communication with Emacs---or @code{nil} if it is using pipes
-instead of a terminal (see @code{process-connection-type} in
address@hidden Processes}).
address@hidden defun
-
address@hidden process-coding-system process
address@hidden systems for a subprocess}
-This function returns a cons cell describing the coding systems in use
-for decoding output from @var{process} and for encoding input to
address@hidden (@pxref{Coding Systems}). The value has this form:
-
address@hidden
-(@var{coding-system-for-decoding} . @var{coding-system-for-encoding})
address@hidden example
address@hidden defun
-
address@hidden set-process-coding-system process &optional decoding-system
encoding-system
-This function specifies the coding systems to use for subsequent output
-from and input to @var{process}. It will use @var{decoding-system} to
-decode subprocess output, and @var{encoding-system} to encode subprocess
-input.
address@hidden defun
-
- Every process also has a property list that you can use to store
-miscellaneous values associated with the process.
-
address@hidden process-get process propname
-This function returns the value of the @var{propname} property
-of @var{process}.
address@hidden defun
-
address@hidden process-put process propname value
-This function sets the value of the @var{propname} property
-of @var{process} to @var{value}.
address@hidden defun
-
address@hidden process-plist process
-This function returns the process plist of @var{process}.
address@hidden defun
-
address@hidden set-process-plist process plist
-This function sets the process plist of @var{process} to @var{plist}.
address@hidden defun
-
address@hidden Input to Processes
address@hidden Sending Input to Processes
address@hidden process input
-
- Asynchronous subprocesses receive input when it is sent to them by
-Emacs, which is done with the functions in this section. You must
-specify the process to send input to, and the input data to send. The
-data appears on the ``standard input'' of the subprocess.
-
- Some operating systems have limited space for buffered input in a
address@hidden On these systems, Emacs sends an @acronym{EOF}
-periodically amidst the other characters, to force them through. For
-most programs, these @acronym{EOF}s do no harm.
-
- Subprocess input is normally encoded using a coding system before the
-subprocess receives it, much like text written into a file. You can use
address@hidden to specify which coding system to use
-(@pxref{Process Information}). Otherwise, the coding system comes from
address@hidden, if that is address@hidden; or else from
-the defaulting mechanism (@pxref{Default Coding Systems}).
-
- Sometimes the system is unable to accept input for that process,
-because the input buffer is full. When this happens, the send functions
-wait a short while, accepting output from subprocesses, and then try
-again. This gives the subprocess a chance to read more of its pending
-input and make space in the buffer. It also allows filters, sentinels
-and timers to run---so take account of that in writing your code.
-
- In these functions, the @var{process} argument can be a process or
-the name of a process, or a buffer or buffer name (which stands
-for a process via @code{get-buffer-process}). @code{nil} means
-the current buffer's process.
-
address@hidden process-send-string process string
-This function sends @var{process} the contents of @var{string} as
-standard input. If it is @code{nil}, the current buffer's process is used.
-
- The function returns @code{nil}.
-
address@hidden
address@hidden
-(process-send-string "shell<1>" "ls\n")
- @result{} nil
address@hidden group
-
-
address@hidden
----------- Buffer: *shell* ----------
-...
-introduction.texi syntax-tables.texi~
-introduction.texi~ text.texi
-introduction.txt text.texi~
-...
----------- Buffer: *shell* ----------
address@hidden group
address@hidden smallexample
address@hidden defun
-
address@hidden process-send-region process start end
-This function sends the text in the region defined by @var{start} and
address@hidden as standard input to @var{process}.
-
-An error is signaled unless both @var{start} and @var{end} are
-integers or markers that indicate positions in the current buffer. (It
-is unimportant which number is larger.)
address@hidden defun
-
address@hidden process-send-eof &optional process
-This function makes @var{process} see an end-of-file in its
-input. The @acronym{EOF} comes after any text already sent to it.
-
-The function returns @var{process}.
-
address@hidden
address@hidden
-(process-send-eof "shell")
- @result{} "shell"
address@hidden group
address@hidden smallexample
address@hidden defun
-
address@hidden process-running-child-p process
-This function will tell you whether a subprocess has given control of
-its terminal to its own child process. The value is @code{t} if this is
-true, or if Emacs cannot tell; it is @code{nil} if Emacs can be certain
-that this is not so.
address@hidden defun
-
address@hidden Signals to Processes
address@hidden Sending Signals to Processes
address@hidden process signals
address@hidden sending signals
address@hidden signals
-
- @dfn{Sending a signal} to a subprocess is a way of interrupting its
-activities. There are several different signals, each with its own
-meaning. The set of signals and their names is defined by the operating
-system. For example, the signal @code{SIGINT} means that the user has
-typed @kbd{C-c}, or that some analogous thing has happened.
-
- Each signal has a standard effect on the subprocess. Most signals
-kill the subprocess, but some stop or resume execution instead. Most
-signals can optionally be handled by programs; if the program handles
-the signal, then we can say nothing in general about its effects.
-
- You can send signals explicitly by calling the functions in this
-section. Emacs also sends signals automatically at certain times:
-killing a buffer sends a @code{SIGHUP} signal to all its associated
-processes; killing Emacs sends a @code{SIGHUP} signal to all remaining
-processes. (@code{SIGHUP} is a signal that usually indicates that the
-user hung up the phone.)
-
- Each of the signal-sending functions takes two optional arguments:
address@hidden and @var{current-group}.
-
- The argument @var{process} must be either a process, a process
-name, a buffer, a buffer name, or @code{nil}. A buffer or buffer name
-stands for a process through @code{get-buffer-process}. @code{nil}
-stands for the process associated with the current buffer. An error
-is signaled if @var{process} does not identify a process.
-
- The argument @var{current-group} is a flag that makes a difference
-when you are running a job-control shell as an Emacs subprocess. If it
-is address@hidden, then the signal is sent to the current process-group
-of the terminal that Emacs uses to communicate with the subprocess. If
-the process is a job-control shell, this means the shell's current
-subjob. If it is @code{nil}, the signal is sent to the process group of
-the immediate subprocess of Emacs. If the subprocess is a job-control
-shell, this is the shell itself.
-
- The flag @var{current-group} has no effect when a pipe is used to
-communicate with the subprocess, because the operating system does not
-support the distinction in the case of pipes. For the same reason,
-job-control shells won't work when a pipe is used. See
address@hidden in @ref{Asynchronous Processes}.
-
address@hidden interrupt-process &optional process current-group
-This function interrupts the process @var{process} by sending the
-signal @code{SIGINT}. Outside of Emacs, typing the ``interrupt
-character'' (normally @kbd{C-c} on some systems, and @code{DEL} on
-others) sends this signal. When the argument @var{current-group} is
address@hidden, you can think of this function as ``typing @kbd{C-c}''
-on the terminal by which Emacs talks to the subprocess.
address@hidden defun
-
address@hidden kill-process &optional process current-group
-This function kills the process @var{process} by sending the
-signal @code{SIGKILL}. This signal kills the subprocess immediately,
-and cannot be handled by the subprocess.
address@hidden defun
-
address@hidden quit-process &optional process current-group
-This function sends the signal @code{SIGQUIT} to the process
address@hidden This signal is the one sent by the ``quit
-character'' (usually @kbd{C-b} or @kbd{C-\}) when you are not inside
-Emacs.
address@hidden defun
-
address@hidden stop-process &optional process current-group
-This function stops the process @var{process} by sending the
-signal @code{SIGTSTP}. Use @code{continue-process} to resume its
-execution.
-
-Outside of Emacs, on systems with job control, the ``stop character''
-(usually @kbd{C-z}) normally sends this signal. When
address@hidden is address@hidden, you can think of this function as
-``typing @kbd{C-z}'' on the terminal Emacs uses to communicate with the
-subprocess.
address@hidden defun
-
address@hidden continue-process &optional process current-group
-This function resumes execution of the process @var{process} by sending
-it the signal @code{SIGCONT}. This presumes that @var{process} was
-stopped previously.
address@hidden defun
-
address@hidden Emacs 19 feature
address@hidden signal-process process signal
-This function sends a signal to process @var{process}. The argument
address@hidden specifies which signal to send; it should be an integer.
-
-The @var{process} argument can be a system process @acronym{ID}; that
-allows you to send signals to processes that are not children of
-Emacs.
address@hidden defun
-
address@hidden Output from Processes
address@hidden Receiving Output from Processes
address@hidden process output
address@hidden output from processes
-
- There are two ways to receive the output that a subprocess writes to
-its standard output stream. The output can be inserted in a buffer,
-which is called the associated buffer of the process, or a function
-called the @dfn{filter function} can be called to act on the output. If
-the process has no buffer and no filter function, its output is
-discarded.
-
- When a subprocess terminates, Emacs reads any pending output,
-then stops reading output from that subprocess. Therefore, if the
-subprocess has children that are still live and still producing
-output, Emacs won't receive that output.
-
- Output from a subprocess can arrive only while Emacs is waiting: when
-reading terminal input, in @code{sit-for} and @code{sleep-for}
-(@pxref{Waiting}), and in @code{accept-process-output} (@pxref{Accepting
-Output}). This minimizes the problem of timing errors that usually
-plague parallel programming. For example, you can safely create a
-process and only then specify its buffer or filter function; no output
-can arrive before you finish, if the code in between does not call any
-primitive that waits.
-
address@hidden process-adaptive-read-buffering
-On some systems, when Emacs reads the output from a subprocess, the
-output data is read in very small blocks, potentially resulting in
-very poor performance. This behavior can be remedied to some extent
-by setting the variable @var{process-adaptive-read-buffering} to a
address@hidden value (the default), as it will automatically delay reading
-from such processes, thus allowing them to produce more output before
-Emacs tries to read it.
address@hidden defvar
-
- It is impossible to separate the standard output and standard error
-streams of the subprocess, because Emacs normally spawns the subprocess
-inside a pseudo-TTY, and a pseudo-TTY has only one output channel. If
-you want to keep the output to those streams separate, you should
-redirect one of them to a file---for example, by using an appropriate
-shell command.
-
address@hidden
-* Process Buffers:: If no filter, output is put in a buffer.
-* Filter Functions:: Filter functions accept output from the process.
-* Decoding Output:: Filters can get unibyte or multibyte strings.
-* Accepting Output:: How to wait until process output arrives.
address@hidden menu
-
address@hidden Process Buffers
address@hidden Process Buffers
-
- A process can (and usually does) have an @dfn{associated buffer},
-which is an ordinary Emacs buffer that is used for two purposes: storing
-the output from the process, and deciding when to kill the process. You
-can also use the buffer to identify a process to operate on, since in
-normal practice only one process is associated with any given buffer.
-Many applications of processes also use the buffer for editing input to
-be sent to the process, but this is not built into Emacs Lisp.
-
- Unless the process has a filter function (@pxref{Filter Functions}),
-its output is inserted in the associated buffer. The position to insert
-the output is determined by the @code{process-mark}, which is then
-updated to point to the end of the text just inserted. Usually, but not
-always, the @code{process-mark} is at the end of the buffer.
-
address@hidden process-buffer process
-This function returns the associated buffer of the process
address@hidden
-
address@hidden
address@hidden
-(process-buffer (get-process "shell"))
- @result{} #<buffer *shell*>
address@hidden group
address@hidden smallexample
address@hidden defun
-
address@hidden process-mark process
-This function returns the process marker for @var{process}, which is the
-marker that says where to insert output from the process.
-
-If @var{process} does not have a buffer, @code{process-mark} returns a
-marker that points nowhere.
-
-Insertion of process output in a buffer uses this marker to decide where
-to insert, and updates it to point after the inserted text. That is why
-successive batches of output are inserted consecutively.
-
-Filter functions normally should use this marker in the same fashion
-as is done by direct insertion of output in the buffer. A good
-example of a filter function that uses @code{process-mark} is found at
-the end of the following section.
-
-When the user is expected to enter input in the process buffer for
-transmission to the process, the process marker separates the new input
-from previous output.
address@hidden defun
-
address@hidden set-process-buffer process buffer
-This function sets the buffer associated with @var{process} to
address@hidden If @var{buffer} is @code{nil}, the process becomes
-associated with no buffer.
address@hidden defun
-
address@hidden get-buffer-process buffer-or-name
-This function returns a nondeleted process associated with the buffer
-specified by @var{buffer-or-name}. If there are several processes
-associated with it, this function chooses one (currently, the one most
-recently created, but don't count on that). Deletion of a process
-(see @code{delete-process}) makes it ineligible for this function to
-return.
-
-It is usually a bad idea to have more than one process associated with
-the same buffer.
-
address@hidden
address@hidden
-(get-buffer-process "*shell*")
- @result{} #<process shell>
address@hidden group
address@hidden smallexample
-
-Killing the process's buffer deletes the process, which kills the
-subprocess with a @code{SIGHUP} signal (@pxref{Signals to Processes}).
address@hidden defun
-
address@hidden Filter Functions
address@hidden Process Filter Functions
address@hidden filter function
address@hidden process filter
-
- A process @dfn{filter function} is a function that receives the
-standard output from the associated process. If a process has a filter,
-then @emph{all} output from that process is passed to the filter. The
-process buffer is used directly for output from the process only when
-there is no filter.
-
- The filter function can only be called when Emacs is waiting for
-something, because process output arrives only at such times. Emacs
-waits when reading terminal input, in @code{sit-for} and
address@hidden (@pxref{Waiting}), and in @code{accept-process-output}
-(@pxref{Accepting Output}).
-
- A filter function must accept two arguments: the associated process
-and a string, which is output just received from it. The function is
-then free to do whatever it chooses with the output.
-
- Quitting is normally inhibited within a filter function---otherwise,
-the effect of typing @kbd{C-g} at command level or to quit a user
-command would be unpredictable. If you want to permit quitting inside
-a filter function, bind @code{inhibit-quit} to @code{nil}. In most
-cases, the right way to do this is with the macro
address@hidden @xref{Quitting}.
-
- If an error happens during execution of a filter function, it is
-caught automatically, so that it doesn't stop the execution of whatever
-program was running when the filter function was started. However, if
address@hidden is address@hidden, the error-catching is turned
-off. This makes it possible to use the Lisp debugger to debug the
-filter function. @xref{Debugger}.
-
- Many filter functions sometimes or always insert the text in the
-process's buffer, mimicking the actions of Emacs when there is no
-filter. Such filter functions need to use @code{set-buffer} in order to
-be sure to insert in that buffer. To avoid setting the current buffer
-semipermanently, these filter functions must save and restore the
-current buffer. They should also update the process marker, and in some
-cases update the value of point. Here is how to do these things:
-
address@hidden
address@hidden
-(defun ordinary-insertion-filter (proc string)
- (with-current-buffer (process-buffer proc)
- (let ((moving (= (point) (process-mark proc))))
address@hidden group
address@hidden
- (save-excursion
- ;; @r{Insert the text, advancing the process marker.}
- (goto-char (process-mark proc))
- (insert string)
- (set-marker (process-mark proc) (point)))
- (if moving (goto-char (process-mark proc))))))
address@hidden group
address@hidden smallexample
-
address@hidden
-The reason to use @code{with-current-buffer}, rather than using
address@hidden to save and restore the current buffer, is so as
-to preserve the change in point made by the second call to
address@hidden
-
- To make the filter force the process buffer to be visible whenever new
-text arrives, insert the following line just before the
address@hidden construct:
-
address@hidden
-(display-buffer (process-buffer proc))
address@hidden smallexample
-
- To force point to the end of the new output, no matter where it was
-previously, eliminate the variable @code{moving} and call
address@hidden unconditionally.
-
- In earlier Emacs versions, every filter function that did regular
-expression searching or matching had to explicitly save and restore the
-match data. Now Emacs does this automatically for filter functions;
-they never need to do it explicitly. @xref{Match Data}.
-
- A filter function that writes the output into the buffer of the
-process should check whether the buffer is still alive. If it tries to
-insert into a dead buffer, it will get an error. The expression
address@hidden(buffer-name (process-buffer @var{process}))} returns @code{nil}
-if the buffer is dead.
-
- The output to the function may come in chunks of any size. A program
-that produces the same output twice in a row may send it as one batch of
-200 characters one time, and five batches of 40 characters the next. If
-the filter looks for certain text strings in the subprocess output, make
-sure to handle the case where one of these strings is split across two
-or more batches of output.
-
address@hidden set-process-filter process filter
-This function gives @var{process} the filter function @var{filter}. If
address@hidden is @code{nil}, it gives the process no filter.
address@hidden defun
-
address@hidden process-filter process
-This function returns the filter function of @var{process}, or @code{nil}
-if it has none.
address@hidden defun
-
- Here is an example of use of a filter function:
-
address@hidden
address@hidden
-(defun keep-output (process output)
- (setq kept (cons output kept)))
- @result{} keep-output
address@hidden group
address@hidden
-(setq kept nil)
- @result{} nil
address@hidden group
address@hidden
-(set-process-filter (get-process "shell") 'keep-output)
- @result{} keep-output
address@hidden group
address@hidden
-(process-send-string "shell" "ls ~/other\n")
- @result{} nil
-kept
- @result{} ("lewis@@slug[8] % "
address@hidden group
address@hidden
-"FINAL-W87-SHORT.MSS backup.otl kolstad.mss~
-address.txt backup.psf kolstad.psf
-backup.bib~ david.mss resume-Dec-86.mss~
-backup.err david.psf resume-Dec.psf
-backup.mss dland syllabus.mss
-"
-"#backups.mss# backup.mss~ kolstad.mss
-")
address@hidden group
address@hidden smallexample
-
address@hidden @c The code in this example doesn't show the right way to do
things.
-Here is another, more realistic example, which demonstrates how to use
-the process mark to do insertion in the same fashion as is done when
-there is no filter function:
-
address@hidden
address@hidden
-;; @r{Insert input in the buffer specified by @code{my-shell-buffer}}
-;; @r{and make sure that buffer is shown in some window.}
-(defun my-process-filter (proc str)
- (let ((cur (selected-window))
- (pop-up-windows t))
- (pop-to-buffer my-shell-buffer)
address@hidden group
address@hidden
- (goto-char (point-max))
- (insert str)
- (set-marker (process-mark proc) (point-max))
- (select-window cur)))
address@hidden group
address@hidden smallexample
address@hidden ignore
-
address@hidden Decoding Output
address@hidden Decoding Process Output
address@hidden decode process output
-
- When Emacs writes process output directly into a multibyte buffer,
-it decodes the output according to the process output coding system.
-If the coding system is @code{raw-text} or @code{no-conversion}, Emacs
-converts the unibyte output to multibyte using
address@hidden, and inserts the resulting multibyte text.
-
- You can use @code{set-process-coding-system} to specify which coding
-system to use (@pxref{Process Information}). Otherwise, the coding
-system comes from @code{coding-system-for-read}, if that is
address@hidden; or else from the defaulting mechanism (@pxref{Default
-Coding Systems}).
-
- @strong{Warning:} Coding systems such as @code{undecided} which
-determine the coding system from the data do not work entirely
-reliably with asynchronous subprocess output. This is because Emacs
-has to process asynchronous subprocess output in batches, as it
-arrives. Emacs must try to detect the proper coding system from one
-batch at a time, and this does not always work. Therefore, if at all
-possible, specify a coding system that determines both the character
-code conversion and the end of line conversion---that is, one like
address@hidden, rather than @code{undecided} or @code{latin-1}.
-
address@hidden filter multibyte flag, of process
address@hidden process filter multibyte flag
- When Emacs calls a process filter function, it provides the process
-output as a multibyte string or as a unibyte string according to the
-process's filter multibyte flag. If the flag is address@hidden, Emacs
-decodes the output according to the process output coding system to
-produce a multibyte string, and passes that to the process. If the
-flag is @code{nil}, Emacs puts the output into a unibyte string, with
-no decoding, and passes that.
-
- When you create a process, the filter multibyte flag takes its
-initial value from @code{default-enable-multibyte-characters}. If you
-want to change the flag later on, use
address@hidden
-
address@hidden set-process-filter-multibyte process multibyte
-This function sets the filter multibyte flag of @var{process}
-to @var{multibyte}.
address@hidden defun
-
address@hidden process-filter-multibyte-p process
-This function returns the filter multibyte flag of @var{process}.
address@hidden defun
-
address@hidden Accepting Output
address@hidden Accepting Output from Processes
address@hidden accept input from processes
-
- Output from asynchronous subprocesses normally arrives only while
-Emacs is waiting for some sort of external event, such as elapsed time
-or terminal input. Occasionally it is useful in a Lisp program to
-explicitly permit output to arrive at a specific point, or even to wait
-until output arrives from a process.
-
address@hidden accept-process-output &optional process seconds millisec
just-this-one
-This function allows Emacs to read pending output from processes. The
-output is inserted in the associated buffers or given to their filter
-functions. If @var{process} is address@hidden then this function does
-not return until some output has been received from @var{process}.
-
address@hidden Emacs 19 feature
-The arguments @var{seconds} and @var{millisec} let you specify timeout
-periods. The former specifies a period measured in seconds and the
-latter specifies one measured in milliseconds. The two time periods
-thus specified are added together, and @code{accept-process-output}
-returns after that much time, whether or not there has been any
-subprocess output.
-
-The argument @var{millisec} is semi-obsolete nowadays because
address@hidden can be a floating point number to specify waiting a
-fractional number of seconds. If @var{seconds} is 0, the function
-accepts whatever output is pending but does not wait.
-
address@hidden Emacs 22.1 feature
-If @var{process} is a process, and the argument @var{just-this-one} is
address@hidden, only output from that process is handled, suspending output
-from other processes until some output has been received from that
-process or the timeout expires. If @var{just-this-one} is an integer,
-also inhibit running timers. This feature is generally not
-recommended, but may be necessary for specific applications, such as
-speech synthesis.
-
-The function @code{accept-process-output} returns address@hidden if it
-did get some output, or @code{nil} if the timeout expired before output
-arrived.
address@hidden defun
-
address@hidden Sentinels
address@hidden Sentinels: Detecting Process Status Changes
address@hidden process sentinel
address@hidden sentinel (of process)
-
- A @dfn{process sentinel} is a function that is called whenever the
-associated process changes status for any reason, including signals
-(whether sent by Emacs or caused by the process's own actions) that
-terminate, stop, or continue the process. The process sentinel is
-also called if the process exits. The sentinel receives two
-arguments: the process for which the event occurred, and a string
-describing the type of event.
-
- The string describing the event looks like one of the following:
-
address@hidden @bullet
address@hidden
address@hidden"finished\n"}.
-
address@hidden
address@hidden"exited abnormally with code @var{exitcode}\n"}.
-
address@hidden
address@hidden"@var{name-of-signal}\n"}.
-
address@hidden
address@hidden"@var{name-of-signal} (core dumped)\n"}.
address@hidden itemize
-
- A sentinel runs only while Emacs is waiting (e.g., for terminal
-input, or for time to elapse, or for process output). This avoids the
-timing errors that could result from running them at random places in
-the middle of other Lisp programs. A program can wait, so that
-sentinels will run, by calling @code{sit-for} or @code{sleep-for}
-(@pxref{Waiting}), or @code{accept-process-output} (@pxref{Accepting
-Output}). Emacs also allows sentinels to run when the command loop is
-reading input. @code{delete-process} calls the sentinel when it
-terminates a running process.
-
- Emacs does not keep a queue of multiple reasons to call the sentinel
-of one process; it records just the current status and the fact that
-there has been a change. Therefore two changes in status, coming in
-quick succession, can call the sentinel just once. However, process
-termination will always run the sentinel exactly once. This is
-because the process status can't change again after termination.
-
- Emacs explicitly checks for output from the process before running
-the process sentinel. Once the sentinel runs due to process
-termination, no further output can arrive from the process.
-
- A sentinel that writes the output into the buffer of the process
-should check whether the buffer is still alive. If it tries to insert
-into a dead buffer, it will get an error. If the buffer is dead,
address@hidden(buffer-name (process-buffer @var{process}))} returns @code{nil}.
-
- Quitting is normally inhibited within a sentinel---otherwise, the
-effect of typing @kbd{C-g} at command level or to quit a user command
-would be unpredictable. If you want to permit quitting inside a
-sentinel, bind @code{inhibit-quit} to @code{nil}. In most cases, the
-right way to do this is with the macro @code{with-local-quit}.
address@hidden
-
- If an error happens during execution of a sentinel, it is caught
-automatically, so that it doesn't stop the execution of whatever
-programs was running when the sentinel was started. However, if
address@hidden is address@hidden, the error-catching is turned
-off. This makes it possible to use the Lisp debugger to debug the
-sentinel. @xref{Debugger}.
-
- While a sentinel is running, the process sentinel is temporarily
-set to @code{nil} so that the sentinel won't run recursively.
-For this reason it is not possible for a sentinel to specify
-a new sentinel.
-
- In earlier Emacs versions, every sentinel that did regular expression
-searching or matching had to explicitly save and restore the match data.
-Now Emacs does this automatically for sentinels; they never need to do
-it explicitly. @xref{Match Data}.
-
address@hidden set-process-sentinel process sentinel
-This function associates @var{sentinel} with @var{process}. If
address@hidden is @code{nil}, then the process will have no sentinel.
-The default behavior when there is no sentinel is to insert a message in
-the process's buffer when the process status changes.
-
-Changes in process sentinel take effect immediately---if the sentinel
-is slated to be run but has not been called yet, and you specify a new
-sentinel, the eventual call to the sentinel will use the new one.
-
address@hidden
address@hidden
-(defun msg-me (process event)
- (princ
- (format "Process: %s had the event `%s'" process event)))
-(set-process-sentinel (get-process "shell") 'msg-me)
- @result{} msg-me
address@hidden group
address@hidden
-(kill-process (get-process "shell"))
- @print{} Process: #<process shell> had the event `killed'
- @result{} #<process shell>
address@hidden group
address@hidden smallexample
address@hidden defun
-
address@hidden process-sentinel process
-This function returns the sentinel of @var{process}, or @code{nil} if it
-has none.
address@hidden defun
-
address@hidden waiting-for-user-input-p
-While a sentinel or filter function is running, this function returns
address@hidden if Emacs was waiting for keyboard input from the user at
-the time the sentinel or filter function was called, @code{nil} if it
-was not.
address@hidden defun
-
address@hidden Query Before Exit
address@hidden Querying Before Exit
-
- When Emacs exits, it terminates all its subprocesses by sending them
-the @code{SIGHUP} signal. Because subprocesses may be doing
-valuable work, Emacs normally asks the user to confirm that it is ok
-to terminate them. Each process has a query flag which, if
address@hidden, says that Emacs should ask for confirmation before
-exiting and thus killing that process. The default for the query flag
-is @code{t}, meaning @emph{do} query.
-
address@hidden process-query-on-exit-flag process
-This returns the query flag of @var{process}.
address@hidden defun
-
address@hidden set-process-query-on-exit-flag process flag
-This function sets the query flag of @var{process} to @var{flag}. It
-returns @var{flag}.
-
address@hidden
address@hidden
-;; @r{Don't query about the shell process}
-(set-process-query-on-exit-flag (get-process "shell") nil)
- @result{} t
address@hidden group
address@hidden smallexample
address@hidden defun
-
address@hidden process-kill-without-query process &optional do-query
-This function clears the query flag of @var{process}, so that
-Emacs will not query the user on account of that process.
-
-Actually, the function does more than that: it returns the old value of
-the process's query flag, and sets the query flag to @var{do-query}.
-Please don't use this function to do those things any more---please
-use the newer, cleaner functions @code{process-query-on-exit-flag} and
address@hidden in all but the simplest cases.
-The only way you should use @code{process-kill-without-query} nowadays
-is like this:
-
address@hidden
address@hidden
-;; @r{Don't query about the shell process}
-(process-kill-without-query (get-process "shell"))
address@hidden group
address@hidden smallexample
address@hidden defun
-
address@hidden Transaction Queues
address@hidden Transaction Queues
address@hidden transaction queue
-
-You can use a @dfn{transaction queue} to communicate with a subprocess
-using transactions. First use @code{tq-create} to create a transaction
-queue communicating with a specified process. Then you can call
address@hidden to send a transaction.
-
address@hidden tq-create process
-This function creates and returns a transaction queue communicating with
address@hidden The argument @var{process} should be a subprocess
-capable of sending and receiving streams of bytes. It may be a child
-process, or it may be a TCP connection to a server, possibly on another
-machine.
address@hidden defun
-
address@hidden tq-enqueue queue question regexp closure fn &optional
delay-question
-This function sends a transaction to queue @var{queue}. Specifying the
-queue has the effect of specifying the subprocess to talk to.
-
-The argument @var{question} is the outgoing message that starts the
-transaction. The argument @var{fn} is the function to call when the
-corresponding answer comes back; it is called with two arguments:
address@hidden, and the answer received.
-
-The argument @var{regexp} is a regular expression that should match
-text at the end of the entire answer, but nothing before; that's how
address@hidden determines where the answer ends.
-
-If the argument @var{delay-question} is non-nil, delay sending this
-question until the process has finished replying to any previous
-questions. This produces more reliable results with some processes.
-
-The return value of @code{tq-enqueue} itself is not meaningful.
address@hidden defun
-
address@hidden tq-close queue
-Shut down transaction queue @var{queue}, waiting for all pending transactions
-to complete, and then terminate the connection or child process.
address@hidden defun
-
-Transaction queues are implemented by means of a filter function.
address@hidden Functions}.
-
address@hidden Network
address@hidden Network Connections
address@hidden network connection
address@hidden TCP
address@hidden UDP
-
- Emacs Lisp programs can open stream (TCP) and datagram (UDP) network
-connections to other processes on the same machine or other machines.
-A network connection is handled by Lisp much like a subprocess, and is
-represented by a process object. However, the process you are
-communicating with is not a child of the Emacs process, so it has no
-process @acronym{ID}, and you can't kill it or send it signals. All you
-can do is send and receive data. @code{delete-process} closes the
-connection, but does not kill the program at the other end; that
-program must decide what to do about closure of the connection.
-
- Lisp programs can listen for connections by creating network
-servers. A network server is also represented by a kind of process
-object, but unlike a network connection, the network server never
-transfers data itself. When it receives a connection request, it
-creates a new network connection to represent the connection just
-made. (The network connection inherits certain information, including
-the process plist, from the server.) The network server then goes
-back to listening for more connection requests.
-
- Network connections and servers are created by calling
address@hidden with an argument list consisting of
-keyword/argument pairs, for example @code{:server t} to create a
-server process, or @code{:type 'datagram} to create a datagram
-connection. @xref{Low-Level Network}, for details. You can also use
-the @code{open-network-stream} function described below.
-
- You can distinguish process objects representing network connections
-and servers from those representing subprocesses with the
address@hidden function. The possible status values for
-network connections are @code{open}, @code{closed}, @code{connect},
-and @code{failed}. For a network server, the status is always
address@hidden None of those values is possible for a real
-subprocess. @xref{Process Information}.
-
- You can stop and resume operation of a network process by calling
address@hidden and @code{continue-process}. For a server
-process, being stopped means not accepting new connections. (Up to 5
-connection requests will be queued for when you resume the server; you
-can increase this limit, unless it is imposed by the operating
-system.) For a network stream connection, being stopped means not
-processing input (any arriving input waits until you resume the
-connection). For a datagram connection, some number of packets may be
-queued but input may be lost. You can use the function
address@hidden to determine whether a network connection or
-server is stopped; a address@hidden value means yes.
-
address@hidden open-network-stream name buffer-or-name host service
-This function opens a TCP connection, and returns a process object
-that represents the connection.
-
-The @var{name} argument specifies the name for the process object. It
-is modified as necessary to make it unique.
-
-The @var{buffer-or-name} argument is the buffer to associate with the
-connection. Output from the connection is inserted in the buffer,
-unless you specify a filter function to handle the output. If
address@hidden is @code{nil}, it means that the connection is not
-associated with any buffer.
-
-The arguments @var{host} and @var{service} specify where to connect to;
address@hidden is the host name (a string), and @var{service} is the name of
-a defined network service (a string) or a port number (an integer).
address@hidden defun
-
address@hidden process-contact process &optional key
-This function returns information about how a network process was set
-up. For a connection, when @var{key} is @code{nil}, it returns
address@hidden(@var{hostname} @var{service})} which specifies what you
-connected to.
-
-If @var{key} is @code{t}, the value is the complete status information
-for the connection or server; that is, the list of keywords and values
-specified in @code{make-network-process}, except that some of the
-values represent the current status instead of what you specified:
-
address@hidden @code
address@hidden :buffer
-The associated value is the process buffer.
address@hidden :filter
-The associated value is the process filter function.
address@hidden :sentinel
-The associated value is the process sentinel function.
address@hidden :remote
-In a connection, the address in internal format of the remote peer.
address@hidden :local
-The local address, in internal format.
address@hidden :service
-In a server, if you specified @code{t} for @var{service},
-this value is the actual port number.
address@hidden table
-
address@hidden:local} and @code{:remote} are included even if they were not
-specified explicitly in @code{make-network-process}.
-
-If @var{key} is a keyword, the function returns the value corresponding
-to that keyword.
-
-For an ordinary child process, this function always returns @code{t}.
address@hidden defun
-
address@hidden Network Servers
address@hidden Network Servers
address@hidden network servers
-
- You create a server by calling @code{make-network-process} with
address@hidden:server t}. The server will listen for connection requests from
-clients. When it accepts a client connection request, that creates a
-new network connection, itself a process object, with the following
-parameters:
-
address@hidden @bullet
address@hidden
-The connection's process name is constructed by concatenating the
-server process' @var{name} with a client identification string. The
-client identification string for an IPv4 connection looks like
address@hidden<@address@hidden@address@hidden:@var{p}>}. Otherwise, it is a
-unique number in brackets, as in @samp{<@var{nnn}>}. The number
-is unique for each connection in the Emacs session.
-
address@hidden
-If the server's filter is address@hidden, the connection process does
-not get a separate process buffer; otherwise, Emacs creates a new
-buffer for the purpose. The buffer name is the server's buffer name
-or process name, concatenated with the client identification string.
-
-The server's process buffer value is never used directly by Emacs, but
-it is passed to the log function, which can log connections by
-inserting text there.
-
address@hidden
-The communication type and the process filter and sentinel are
-inherited from those of the server. The server never directly
-uses its filter and sentinel; their sole purpose is to initialize
-connections made to the server.
-
address@hidden
-The connection's process contact info is set according to the client's
-addressing information (typically an IP address and a port number).
-This information is associated with the @code{process-contact}
-keywords @code{:host}, @code{:service}, @code{:remote}.
-
address@hidden
-The connection's local address is set up according to the port
-number used for the connection.
-
address@hidden
-The client process' plist is initialized from the server's plist.
address@hidden itemize
-
address@hidden Datagrams
address@hidden Datagrams
address@hidden datagrams
-
- A datagram connection communicates with individual packets rather
-than streams of data. Each call to @code{process-send} sends one
-datagram packet (@pxref{Input to Processes}), and each datagram
-received results in one call to the filter function.
-
- The datagram connection doesn't have to talk with the same remote
-peer all the time. It has a @dfn{remote peer address} which specifies
-where to send datagrams to. Each time an incoming datagram is passed
-to the filter function, the peer address is set to the address that
-datagram came from; that way, if the filter function sends a datagram,
-it will go back to that place. You can specify the remote peer
-address when you create the datagram connection using the
address@hidden:remote} keyword. You can change it later on by calling
address@hidden
-
address@hidden process-datagram-address process
-If @var{process} is a datagram connection or server, this function
-returns its remote peer address.
address@hidden defun
-
address@hidden set-process-datagram-address process address
-If @var{process} is a datagram connection or server, this function
-sets its remote peer address to @var{address}.
address@hidden defun
-
address@hidden Low-Level Network
address@hidden Low-Level Network Access
-
- You can also create network connections by operating at a lower
-level than that of @code{open-network-stream}, using
address@hidden
-
address@hidden
-* Proc: Network Processes. Using @code{make-network-process}.
-* Options: Network Options. Further control over network connections.
-* Features: Network Feature Testing.
- Determining which network features work on
- the machine you are using.
address@hidden menu
-
address@hidden Network Processes
address@hidden @code{make-network-process}
-
- The basic function for creating network connections and network
-servers is @code{make-network-process}. It can do either of those
-jobs, depending on the arguments you give it.
-
address@hidden make-network-process &rest args
-This function creates a network connection or server and returns the
-process object that represents it. The arguments @var{args} are a
-list of keyword/argument pairs. Omitting a keyword is always
-equivalent to specifying it with value @code{nil}, except for
address@hidden:coding}, @code{:filter-multibyte}, and @code{:reuseaddr}. Here
-are the meaningful keywords:
-
address@hidden @asis
address@hidden :name @var{name}
-Use the string @var{name} as the process name. It is modified if
-necessary to make it unique.
-
address@hidden :type @var{type}
-Specify the communication type. A value of @code{nil} specifies a
-stream connection (the default); @code{datagram} specifies a datagram
-connection. Both connections and servers can be of either type.
-
address@hidden :server @var{server-flag}
-If @var{server-flag} is address@hidden, create a server. Otherwise,
-create a connection. For a stream type server, @var{server-flag} may
-be an integer which then specifies the length of the queue of pending
-connections to the server. The default queue length is 5.
-
address@hidden :host @var{host}
-Specify the host to connect to. @var{host} should be a host name or
-Internet address, as a string, or the symbol @code{local} to specify
-the local host. If you specify @var{host} for a server, it must
-specify a valid address for the local host, and only clients
-connecting to that address will be accepted.
-
address@hidden :service @var{service}
address@hidden specifies a port number to connect to, or, for a server,
-the port number to listen on. It should be a service name that
-translates to a port number, or an integer specifying the port number
-directly. For a server, it can also be @code{t}, which means to let
-the system select an unused port number.
-
address@hidden :family @var{family}
address@hidden specifies the address (and protocol) family for
-communication. @code{nil} means determine the proper address family
-automatically for the given @var{host} and @var{service}.
address@hidden specifies a Unix socket, in which case @var{host} is
-ignored. @code{ipv4} and @code{ipv6} specify to use IPv4 and IPv6
-respectively.
-
address@hidden :local @var{local-address}
-For a server process, @var{local-address} is the address to listen on.
-It overrides @var{family}, @var{host} and @var{service}, and you
-may as well not specify them.
-
address@hidden :remote @var{remote-address}
-For a connection, @var{remote-address} is the address to connect to.
-It overrides @var{family}, @var{host} and @var{service}, and you
-may as well not specify them.
-
-For a datagram server, @var{remote-address} specifies the initial
-setting of the remote datagram address.
-
-The format of @var{local-address} or @var{remote-address} depends on
-the address family:
-
address@hidden -
address@hidden
-An IPv4 address is represented as a five-element vector of four 8-bit
-integers and one 16-bit integer
address@hidden@var{a} @var{b} @var{c} @var{d} @var{p}]} corresponding to
-numeric IPv4 address @address@hidden@address@hidden and port number
address@hidden
-
address@hidden
-An IPv6 address is represented as a nine-element vector of 16-bit
-integers @address@hidden @var{b} @var{c} @var{d} @var{e} @var{f}
address@hidden @var{h} @var{p}]} corresponding to numeric IPv6 address
address@hidden:@var{b}:@var{c}:@var{d}:@var{e}:@var{f}:@var{g}:@var{h} and
-port number @var{p}.
-
address@hidden
-A local address is represented as a string which specifies the address
-in the local address space.
-
address@hidden
-An ``unsupported family'' address is represented by a cons
address@hidden(@var{f} . @var{av})}, where @var{f} is the family number and
address@hidden is a vector specifying the socket address using one element
-per address data byte. Do not rely on this format in portable code,
-as it may depend on implementation defined constants, data sizes, and
-data structure alignment.
address@hidden itemize
-
address@hidden :nowait @var{bool}
-If @var{bool} is address@hidden for a stream connection, return
-without waiting for the connection to complete. When the connection
-succeeds or fails, Emacs will call the sentinel function, with a
-second argument matching @code{"open"} (if successful) or
address@hidden"failed"}. The default is to block, so that
address@hidden does not return until the connection
-has succeeded or failed.
-
address@hidden :stop @var{stopped}
-Start the network connection or server in the `stopped' state if
address@hidden is address@hidden
-
address@hidden :buffer @var{buffer}
-Use @var{buffer} as the process buffer.
-
address@hidden :coding @var{coding}
-Use @var{coding} as the coding system for this process. To specify
-different coding systems for decoding data from the connection and for
-encoding data sent to it, specify @code{(@var{decoding} .
address@hidden)} for @var{coding}.
-
-If you don't specify this keyword at all, the default
-is to determine the coding systems from the data.
-
address@hidden :noquery @var{query-flag}
-Initialize the process query flag to @var{query-flag}.
address@hidden Before Exit}.
-
address@hidden :filter @var{filter}
-Initialize the process filter to @var{filter}.
-
address@hidden :filter-multibyte @var{bool}
-If @var{bool} is address@hidden, strings given to the process filter
-are multibyte, otherwise they are unibyte. If you don't specify this
-keyword at all, the default is that the strings are multibyte if
address@hidden is address@hidden
-
address@hidden :sentinel @var{sentinel}
-Initialize the process sentinel to @var{sentinel}.
-
address@hidden :log @var{log}
-Initialize the log function of a server process to @var{log}. The log
-function is called each time the server accepts a network connection
-from a client. The arguments passed to the log function are
address@hidden, @var{connection}, and @var{message}, where @var{server}
-is the server process, @var{connection} is the new process for the
-connection, and @var{message} is a string describing what has
-happened.
-
address@hidden :plist @var{plist}
-Initialize the process plist to @var{plist}.
address@hidden table
-
-The original argument list, modified with the actual connection
-information, is available via the @code{process-contact} function.
address@hidden defun
-
address@hidden Network Options
address@hidden Network Options
-
- The following network options can be specified when you create a
-network process. Except for @code{:reuseaddr}, you can also set or
-modify these options later, using @code{set-network-process-option}.
-
- For a server process, the options specified with
address@hidden are not inherited by the client
-connections, so you will need to set the necessary options for each
-child connection as it is created.
-
address@hidden @asis
address@hidden :bindtodevice @var{device-name}
-If @var{device-name} is a non-empty string identifying a network
-interface name (see @code{network-interface-list}), only handle
-packets received on that interface. If @var{device-name} is @code{nil}
-(the default), handle packets received on any interface.
-
-Using this option may require special privileges on some systems.
-
address@hidden :broadcast @var{broadcast-flag}
-If @var{broadcast-flag} is address@hidden for a datagram process, the
-process will receive datagram packet sent to a broadcast address, and
-be able to send packets to a broadcast address. Ignored for a stream
-connection.
-
address@hidden :dontroute @var{dontroute-flag}
-If @var{dontroute-flag} is address@hidden, the process can only send
-to hosts on the same network as the local host.
-
address@hidden :keepalive @var{keepalive-flag}
-If @var{keepalive-flag} is address@hidden for a stream connection,
-enable exchange of low-level keep-alive messages.
-
address@hidden :linger @var{linger-arg}
-If @var{linger-arg} is address@hidden, wait for successful
-transmission of all queued packets on the connection before it is
-deleted (see @code{delete-process}). If @var{linger-arg} is an
-integer, it specifies the maximum time in seconds to wait for queued
-packets to be sent before closing the connection. Default is
address@hidden which means to discard unsent queued packets when the
-process is deleted.
-
address@hidden :oobinline @var{oobinline-flag}
-If @var{oobinline-flag} is address@hidden for a stream connection,
-receive out-of-band data in the normal data stream. Otherwise, ignore
-out-of-band data.
-
address@hidden :priority @var{priority}
-Set the priority for packets sent on this connection to the integer
address@hidden The interpretation of this number is protocol
-specific, such as setting the TOS (type of service) field on IP
-packets sent on this connection. It may also have system dependent
-effects, such as selecting a specific output queue on the network
-interface.
-
address@hidden :reuseaddr @var{reuseaddr-flag}
-If @var{reuseaddr-flag} is address@hidden (the default) for a stream
-server process, allow this server to reuse a specific port number (see
address@hidden:service}) unless another process on this host is already
-listening on that port. If @var{reuseaddr-flag} is @code{nil}, there
-may be a period of time after the last use of that port (by any
-process on the host), where it is not possible to make a new server on
-that port.
address@hidden table
-
address@hidden set-network-process-option process option value
-This function sets or modifies a network option for network process
address@hidden See @code{make-network-process} for details of options
address@hidden and their corresponding values @var{value}.
-
-The current setting of an option is available via the
address@hidden function.
address@hidden defun
-
address@hidden Network Feature Testing
address@hidden Testing Availability of Network Features
-
- To test for the availability of a given network feature, use
address@hidden like this:
-
address@hidden
-(featurep 'make-network-process '(@var{keyword} @var{value}))
address@hidden example
-
address@hidden
-The result of the first form is @code{t} if it works to specify
address@hidden with value @var{value} in @code{make-network-process}.
-The result of the second form is @code{t} if @var{keyword} is
-supported by @code{make-network-process}. Here are some of the
address@hidden@var{value} pairs you can test in
-this way.
-
address@hidden @code
address@hidden (:nowait t)
address@hidden if non-blocking connect is supported.
address@hidden (:type datagram)
address@hidden if datagrams are supported.
address@hidden (:family local)
address@hidden if local (a.k.a.@: ``UNIX domain'') sockets are supported.
address@hidden (:family ipv6)
address@hidden if IPv6 is supported.
address@hidden (:service t)
address@hidden if the system can select the port for a server.
address@hidden table
-
- To test for the availability of a given network option, use
address@hidden like this:
-
address@hidden
-(featurep 'make-network-process '@var{keyword})
address@hidden example
-
address@hidden
-Here are some of the options you can test in this way.
-
address@hidden @code
address@hidden :bindtodevice
address@hidden :broadcast
address@hidden :dontroute
address@hidden :keepalive
address@hidden :linger
address@hidden :oobinline
address@hidden :priority
address@hidden :reuseaddr
-That particular network option is supported by
address@hidden and @code{set-network-process-option}.
address@hidden table
-
address@hidden Misc Network
address@hidden Misc Network Facilities
-
- These additional functions are useful for creating and operating
-on network connections.
-
address@hidden network-interface-list
-This function returns a list describing the network interfaces
-of the machine you are using. The value is an alist whose
-elements have the form @code{(@var{name} . @var{address})}.
address@hidden has the same form as the @var{local-address}
-and @var{remote-address} arguments to @code{make-network-process}.
address@hidden defun
-
address@hidden network-interface-info ifname
-This function returns information about the network interface named
address@hidden The value is a list of the form
address@hidden(@var{addr} @var{bcast} @var{netmask} @var{hwaddr} @var{flags})}.
-
address@hidden @var
address@hidden addr
-The Internet protocol address.
address@hidden bcast
-The broadcast address.
address@hidden netmask
-The network mask.
address@hidden hwaddr
-The layer 2 address (Ethernet MAC address, for instance).
address@hidden flags
-The current flags of the interface.
address@hidden table
address@hidden defun
-
address@hidden format-network-address address &optional omit-port
-This function converts the Lisp representation of a network address to
-a string.
-
-A five-element vector @address@hidden @var{b} @var{c} @var{d} @var{p}]}
-represents an IPv4 address @address@hidden@address@hidden and port
-number @var{p}. @code{format-network-address} converts that to the
-string @code{"@address@hidden@address@hidden:@var{p}"}.
-
-A nine-element vector @address@hidden @var{b} @var{c} @var{d} @var{e}
address@hidden @var{g} @var{h} @var{p}]} represents an IPv6 address along
-with a port number. @code{format-network-address} converts that to
-the string
address@hidden"address@hidden:@var{b}:@var{c}:@var{d}:@var{e}:@var{f}:@var{g}:@var{h}]:@var{p}"}.
-
-If the vector does not include the port number, @var{p}, or if
address@hidden is address@hidden, the result does not include the
address@hidden:@var{p}} suffix.
address@hidden defun
-
address@hidden Byte Packing
address@hidden Packing and Unpacking Byte Arrays
address@hidden byte packing and unpacking
-
- This section describes how to pack and unpack arrays of bytes,
-usually for binary network protocols. These functions convert byte arrays
-to alists, and vice versa. The byte array can be represented as a
-unibyte string or as a vector of integers, while the alist associates
-symbols either with fixed-size objects or with recursive sub-alists.
-
address@hidden serializing
address@hidden deserializing
address@hidden packing
address@hidden unpacking
- Conversion from byte arrays to nested alists is also known as
address@hidden or @dfn{unpacking}, while going in the opposite
-direction is also known as @dfn{serializing} or @dfn{packing}.
-
address@hidden
-* Bindat Spec:: Describing data layout.
-* Bindat Functions:: Doing the unpacking and packing.
-* Bindat Examples:: Samples of what bindat.el can do for you!
address@hidden menu
-
address@hidden Bindat Spec
address@hidden Describing Data Layout
-
- To control unpacking and packing, you write a @dfn{data layout
-specification}, a special nested list describing named and typed
address@hidden This specification controls length of each field to be
-processed, and how to pack or unpack it. We normally keep bindat specs
-in variables whose names end in @samp{-bindat-spec}; that kind of name
-is automatically recognized as ``risky.''
-
address@hidden endianness
address@hidden big endian
address@hidden little endian
address@hidden network byte ordering
- A field's @dfn{type} describes the size (in bytes) of the object
-that the field represents and, in the case of multibyte fields, how
-the bytes are ordered within the field. The two possible orderings
-are ``big endian'' (also known as ``network byte ordering'') and
-``little endian.'' For instance, the number @code{#x23cd} (decimal
-9165) in big endian would be the two bytes @code{#x23} @code{#xcd};
-and in little endian, @code{#xcd} @code{#x23}. Here are the possible
-type values:
-
address@hidden @code
address@hidden u8
address@hidden byte
-Unsigned byte, with length 1.
-
address@hidden u16
address@hidden word
address@hidden short
-Unsigned integer in network byte order, with length 2.
-
address@hidden u24
-Unsigned integer in network byte order, with length 3.
-
address@hidden u32
address@hidden dword
address@hidden long
-Unsigned integer in network byte order, with length 4.
-Note: These values may be limited by Emacs' integer implementation limits.
-
address@hidden u16r
address@hidden u24r
address@hidden u32r
-Unsigned integer in little endian order, with length 2, 3 and 4, respectively.
-
address@hidden str @var{len}
-String of length @var{len}.
-
address@hidden strz @var{len}
-Zero-terminated string, in a fixed-size field with length @var{len}.
-
address@hidden vec @var{len} address@hidden
-Vector of @var{len} elements of type @var{type}, or bytes if not
address@hidden is specified.
-The @var{type} is any of the simple types above, or another vector
-specified as a list @code{(vec @var{len} address@hidden)}.
-
address@hidden ip
-Four-byte vector representing an Internet address. For example:
address@hidden 0 0 1]} for localhost.
-
address@hidden bits @var{len}
-List of set bits in @var{len} bytes. The bytes are taken in big
-endian order and the bits are numbered starting with @code{8 *
address@hidden @minus{} 1} and ending with zero. For example: @code{bits
-2} unpacks @code{#x28} @code{#x1c} to @code{(2 3 4 11 13)} and
address@hidden @code{#x28} to @code{(3 5 10 11 12)}.
-
address@hidden (eval @var{form})
address@hidden is a Lisp expression evaluated at the moment the field is
-unpacked or packed. The result of the evaluation should be one of the
-above-listed type specifications.
address@hidden table
-
-For a fixed-size field, the length @var{len} is given as an integer
-specifying the number of bytes in the field.
-
-When the length of a field is not fixed, it typically depends on the
-value of a preceding field. In this case, the length @var{len} can be
-given either as a list @code{(@var{name} ...)} identifying a
address@hidden name} in the format specified for @code{bindat-get-field}
-below, or by an expression @code{(eval @var{form})} where @var{form}
-should evaluate to an integer, specifying the field length.
-
-A field specification generally has the form @code{(address@hidden
address@hidden)}. The square braces indicate that @var{name} is
-optional. (Don't use names that are symbols meaningful as type
-specifications (above) or handler specifications (below), since that
-would be ambiguous.) @var{name} can be a symbol or the expression
address@hidden(eval @var{form})}, in which case @var{form} should evaluate to
-a symbol.
-
address@hidden describes how to unpack or pack the field and can be one
-of the following:
-
address@hidden @code
address@hidden @var{type}
-Unpack/pack this field according to the type specification @var{type}.
-
address@hidden eval @var{form}
-Evaluate @var{form}, a Lisp expression, for side-effect only. If the
-field name is specified, the value is bound to that field name.
-
address@hidden fill @var{len}
-Skip @var{len} bytes. In packing, this leaves them unchanged,
-which normally means they remain zero. In unpacking, this means
-they are ignored.
-
address@hidden align @var{len}
-Skip to the next multiple of @var{len} bytes.
-
address@hidden struct @var{spec-name}
-Process @var{spec-name} as a sub-specification. This describes a
-structure nested within another structure.
-
address@hidden union @var{form} (@var{tag} @var{spec})@dots{}
address@hidden ??? I don't see how one would actually use this.
address@hidden ??? what kind of expression would be useful for @var{form}?
-Evaluate @var{form}, a Lisp expression, find the first @var{tag}
-that matches it, and process its associated data layout specification
address@hidden Matching can occur in one of three ways:
-
address@hidden
address@hidden
-If a @var{tag} has the form @code{(eval @var{expr})}, evaluate
address@hidden with the variable @code{tag} dynamically bound to the value
-of @var{form}. A address@hidden result indicates a match.
-
address@hidden
address@hidden matches if it is @code{equal} to the value of @var{form}.
-
address@hidden
address@hidden matches unconditionally if it is @code{t}.
address@hidden itemize
-
address@hidden repeat @var{count} @address@hidden
-Process the @var{field-specs} recursively, in order, then repeat
-starting from the first one, processing all the specs @var{count}
-times overall. The @var{count} is given using the same formats as a
-field length---if an @code{eval} form is used, it is evaluated just once.
-For correct operation, each spec in @var{field-specs} must include a name.
address@hidden table
-
-For the @code{(eval @var{form})} forms used in a bindat specification,
-the @var{form} can access and update these dynamically bound variables
-during evaluation:
-
address@hidden @code
address@hidden last
-Value of the last field processed.
-
address@hidden bindat-raw
-The data as a byte array.
-
address@hidden bindat-idx
-Current index (within @code{bindat-raw}) for unpacking or packing.
-
address@hidden struct
-The alist containing the structured data that have been unpacked so
-far, or the entire structure being packed. You can use
address@hidden to access specific fields of this structure.
-
address@hidden count
address@hidden index
-Inside a @code{repeat} block, these contain the maximum number of
-repetitions (as specified by the @var{count} parameter), and the
-current repetition number (counting from 0). Setting @code{count} to
-zero will terminate the inner-most repeat block after the current
-repetition has completed.
address@hidden table
-
address@hidden Bindat Functions
address@hidden Functions to Unpack and Pack Bytes
-
- In the following documentation, @var{spec} refers to a data layout
-specification, @code{bindat-raw} to a byte array, and @var{struct} to an
-alist representing unpacked field data.
-
address@hidden bindat-unpack spec bindat-raw &optional bindat-idx
-This function unpacks data from the unibyte string or byte
-array @code{bindat-raw}
-according to @var{spec}. Normally this starts unpacking at the
-beginning of the byte array, but if @var{bindat-idx} is address@hidden, it
-specifies a zero-based starting position to use instead.
-
-The value is an alist or nested alist in which each element describes
-one unpacked field.
address@hidden defun
-
address@hidden bindat-get-field struct &rest name
-This function selects a field's data from the nested alist
address@hidden Usually @var{struct} was returned by
address@hidden If @var{name} corresponds to just one argument,
-that means to extract a top-level field value. Multiple @var{name}
-arguments specify repeated lookup of sub-structures. An integer name
-acts as an array index.
-
-For example, if @var{name} is @code{(a b 2 c)}, that means to find
-field @code{c} in the third element of subfield @code{b} of field
address@hidden (This corresponds to @code{struct.a.b[2].c} in C.)
address@hidden defun
-
- Although packing and unpacking operations change the organization of
-data (in memory), they preserve the data's @dfn{total length}, which is
-the sum of all the fields' lengths, in bytes. This value is not
-generally inherent in either the specification or alist alone; instead,
-both pieces of information contribute to its calculation. Likewise, the
-length of a string or array being unpacked may be longer than the data's
-total length as described by the specification.
-
address@hidden bindat-length spec struct
-This function returns the total length of the data in @var{struct},
-according to @var{spec}.
address@hidden defun
-
address@hidden bindat-pack spec struct &optional bindat-raw bindat-idx
-This function returns a byte array packed according to @var{spec} from
-the data in the alist @var{struct}. Normally it creates and fills a
-new byte array starting at the beginning. However, if @var{bindat-raw}
-is address@hidden, it specifies a pre-allocated unibyte string or vector to
-pack into. If @var{bindat-idx} is address@hidden, it specifies the starting
-offset for packing into @code{bindat-raw}.
-
-When pre-allocating, you should make sure @code{(length @var{bindat-raw})}
-meets or exceeds the total length to avoid an out-of-range error.
address@hidden defun
-
address@hidden bindat-ip-to-string ip
-Convert the Internet address vector @var{ip} to a string in the usual
-dotted notation.
-
address@hidden
-(bindat-ip-to-string [127 0 0 1])
- @result{} "127.0.0.1"
address@hidden example
address@hidden defun
-
address@hidden Bindat Examples
address@hidden Examples of Byte Unpacking and Packing
-
- Here is a complete example of byte unpacking and packing:
-
address@hidden
-(defvar fcookie-index-spec
- '((:version u32)
- (:count u32)
- (:longest u32)
- (:shortest u32)
- (:flags u32)
- (:delim u8)
- (:ignored fill 3)
- (:offset repeat (:count)
- (:foo u32)))
- "Description of a fortune cookie index file's contents.")
-
-(defun fcookie (cookies &optional index)
- "Display a random fortune cookie from file COOKIES.
-Optional second arg INDEX specifies the associated index
-filename, which is by default constructed by appending
-\".dat\" to COOKIES. Display cookie text in possibly
-new buffer \"*Fortune Cookie: BASENAME*\" where BASENAME
-is COOKIES without the directory part."
- (interactive "fCookies file: ")
- (let* ((info (with-temp-buffer
- (insert-file-contents-literally
- (or index (concat cookies ".dat")))
- (bindat-unpack fcookie-index-spec
- (buffer-string))))
- (sel (random (bindat-get-field info :count)))
- (beg (cdar (bindat-get-field info :offset sel)))
- (end (or (cdar (bindat-get-field info
- :offset (1+ sel)))
- (nth 7 (file-attributes cookies)))))
- (switch-to-buffer
- (get-buffer-create
- (format "*Fortune Cookie: %s*"
- (file-name-nondirectory cookies))))
- (erase-buffer)
- (insert-file-contents-literally
- cookies nil beg (- end 3))))
-
-(defun fcookie-create-index (cookies &optional index delim)
- "Scan file COOKIES, and write out its index file.
-Optional second arg INDEX specifies the index filename,
-which is by default constructed by appending \".dat\" to
-COOKIES. Optional third arg DELIM specifies the unibyte
-character which, when found on a line of its own in
-COOKIES, indicates the border between entries."
- (interactive "fCookies file: ")
- (setq delim (or delim ?%))
- (let ((delim-line (format "\n%c\n" delim))
- (count 0)
- (max 0)
- min p q len offsets)
- (unless (= 3 (string-bytes delim-line))
- (error "Delimiter cannot be represented in one byte"))
- (with-temp-buffer
- (insert-file-contents-literally cookies)
- (while (and (setq p (point))
- (search-forward delim-line (point-max) t)
- (setq len (- (point) 3 p)))
- (setq count (1+ count)
- max (max max len)
- min (min (or min max) len)
- offsets (cons (1- p) offsets))))
- (with-temp-buffer
- (set-buffer-multibyte nil)
- (insert
- (bindat-pack
- fcookie-index-spec
- `((:version . 2)
- (:count . ,count)
- (:longest . ,max)
- (:shortest . ,min)
- (:flags . 0)
- (:delim . ,delim)
- (:offset . ,(mapcar (lambda (o)
- (list (cons :foo o)))
- (nreverse offsets))))))
- (let ((coding-system-for-write 'raw-text-unix))
- (write-file (or index (concat cookies ".dat")))))))
address@hidden lisp
-
-Following is an example of defining and unpacking a complex structure.
-Consider the following C structures:
-
address@hidden
-struct header @{
- unsigned long dest_ip;
- unsigned long src_ip;
- unsigned short dest_port;
- unsigned short src_port;
address@hidden;
-
-struct data @{
- unsigned char type;
- unsigned char opcode;
- unsigned short length; /* In network byte order */
- unsigned char id[8]; /* null-terminated string */
- unsigned char data[/* (length + 3) & ~3 */];
address@hidden;
-
-struct packet @{
- struct header header;
- unsigned long counters[2]; /* In little endian order */
- unsigned char items;
- unsigned char filler[3];
- struct data item[/* items */];
-
address@hidden;
address@hidden example
-
-The corresponding data layout specification:
-
address@hidden
-(setq header-spec
- '((dest-ip ip)
- (src-ip ip)
- (dest-port u16)
- (src-port u16)))
-
-(setq data-spec
- '((type u8)
- (opcode u8)
- (length u16) ;; network byte order
- (id strz 8)
- (data vec (length))
- (align 4)))
-
-(setq packet-spec
- '((header struct header-spec)
- (counters vec 2 u32r) ;; little endian order
- (items u8)
- (fill 3)
- (item repeat (items)
- (struct data-spec))))
address@hidden lisp
-
-A binary data representation:
-
address@hidden
-(setq binary-data
- [ 192 168 1 100 192 168 1 101 01 28 21 32
- 160 134 1 0 5 1 0 0 2 0 0 0
- 2 3 0 5 ?A ?B ?C ?D ?E ?F 0 0 1 2 3 4 5 0 0 0
- 1 4 0 7 ?B ?C ?D ?E ?F ?G 0 0 6 7 8 9 10 11 12 0 ])
address@hidden lisp
-
-The corresponding decoded structure:
-
address@hidden
-(setq decoded (bindat-unpack packet-spec binary-data))
- @result{}
-((header
- (dest-ip . [192 168 1 100])
- (src-ip . [192 168 1 101])
- (dest-port . 284)
- (src-port . 5408))
- (counters . [100000 261])
- (items . 2)
- (item ((data . [1 2 3 4 5])
- (id . "ABCDEF")
- (length . 5)
- (opcode . 3)
- (type . 2))
- ((data . [6 7 8 9 10 11 12])
- (id . "BCDEFG")
- (length . 7)
- (opcode . 4)
- (type . 1))))
address@hidden lisp
-
-Fetching data from this structure:
-
address@hidden
-(bindat-get-field decoded 'item 1 'id)
- @result{} "BCDEFG"
address@hidden lisp
-
address@hidden
- arch-tag: ba9da253-e65f-4e7f-b727-08fba0a1df7a
address@hidden ignore
- [Emacs-diffs] Changes to processes.texi,
Glenn Morris <=