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[Emacs-diffs] Changes to building.texi
|
From: |
Glenn Morris |
|
Subject: |
[Emacs-diffs] Changes to building.texi |
|
Date: |
Thu, 06 Sep 2007 04:44:24 +0000 |
CVSROOT: /sources/emacs
Module name: emacs
Changes by: Glenn Morris <gm> 07/09/06 04:44:24
Index: building.texi
===================================================================
RCS file: building.texi
diff -N building.texi
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ building.texi 6 Sep 2007 04:44:24 -0000 1.1
@@ -0,0 +1,1440 @@
address@hidden This is part of the Emacs manual.
address@hidden Copyright (C) 1985, 1986, 1987, 1993, 1994, 1995, 1997, 2000,
2001,
address@hidden 2002, 2003, 2004, 2005, 2006, 2007 Free Software Foundation,
Inc.
address@hidden See file emacs.texi for copying conditions.
address@hidden Building, Maintaining, Programs, Top
address@hidden Compiling and Testing Programs
address@hidden building programs
address@hidden program building
address@hidden running Lisp functions
+
+ The previous chapter discusses the Emacs commands that are useful for
+making changes in programs. This chapter deals with commands that assist
+in the larger process of compiling and testing programs.
+
address@hidden
+* Compilation:: Compiling programs in languages other
+ than Lisp (C, Pascal, etc.).
+* Compilation Mode:: The mode for visiting compiler errors.
+* Compilation Shell:: Customizing your shell properly
+ for use in the compilation buffer.
+* Grep Searching:: Searching with grep.
+* Flymake:: Finding syntax errors on the fly.
+* Debuggers:: Running symbolic debuggers for non-Lisp programs.
+* Executing Lisp:: Various modes for editing Lisp programs,
+ with different facilities for running
+ the Lisp programs.
+* Libraries: Lisp Libraries. Creating Lisp programs to run in Emacs.
+* Eval: Lisp Eval. Executing a single Lisp expression in Emacs.
+* Interaction: Lisp Interaction. Executing Lisp in an Emacs buffer.
+* External Lisp:: Communicating through Emacs with a separate Lisp.
address@hidden menu
+
address@hidden Compilation
address@hidden Running Compilations under Emacs
address@hidden inferior process
address@hidden make
address@hidden compilation errors
address@hidden error log
+
+ Emacs can run compilers for noninteractive languages such as C and
+Fortran as inferior processes, feeding the error log into an Emacs buffer.
+It can also parse the error messages and show you the source lines where
+compilation errors occurred.
+
address@hidden @kbd
address@hidden M-x compile
+Run a compiler asynchronously under Emacs, with error messages going to
+the @samp{*compilation*} buffer.
address@hidden M-x recompile
+Invoke a compiler with the same command as in the last invocation of
address@hidden compile}.
address@hidden M-x kill-compilation
+Kill the running compilation subprocess.
address@hidden table
+
address@hidden compile
+ To run @code{make} or another compilation command, do @kbd{M-x
+compile}. This command reads a shell command line using the minibuffer,
+and then executes the command in an inferior shell, putting output in
+the buffer named @samp{*compilation*}. The current buffer's default
+directory is used as the working directory for the execution of the
+command; normally, therefore, the compilation happens in this
+directory.
+
address@hidden compile-command
+ The default for the compilation command is normally @samp{make -k},
+which is correct most of the time for nontrivial programs.
+(@xref{Top,, Make, make, GNU Make Manual}.) If you have done @kbd{M-x
+compile} before, the default each time is the command you used the
+previous time. @code{compile} stores this command in the variable
address@hidden, so setting that variable specifies the default
+for the next use of @kbd{M-x compile}. If a file specifies a file
+local value for @code{compile-command}, that provides the default when
+you type @kbd{M-x compile} in that file's buffer. @xref{File
+Variables}.
+
+ Starting a compilation displays the buffer @samp{*compilation*} in
+another window but does not select it. The buffer's mode line tells
+you whether compilation is finished, with the word @samp{run},
address@hidden or @samp{exit} inside the parentheses. You do not have
+to keep this buffer visible; compilation continues in any case. While
+a compilation is going on, the string @samp{Compiling} appears in the
+mode lines of all windows. When this string disappears, the
+compilation is finished.
+
+ If you want to watch the compilation transcript as it appears, switch
+to the @samp{*compilation*} buffer and move point to the end of the
+buffer. When point is at the end, new compilation output is inserted
+above point, which remains at the end. If point is not at the end of
+the buffer, it remains fixed while more compilation output is added at
+the end of the buffer.
+
address@hidden compilation buffer, keeping point at end
address@hidden compilation-scroll-output
+ If you set the variable @code{compilation-scroll-output} to a
address@hidden value, then the compilation buffer always scrolls to
+follow output as it comes in.
+
address@hidden recompile
+ To rerun the last compilation with the same command, type @kbd{M-x
+recompile}. This automatically reuses the compilation command from
+the last invocation of @kbd{M-x compile}. It also reuses the
address@hidden buffer and starts the compilation in its default
+directory, which is the directory in which the previous compilation
+was started.
+
+ When the compiler process terminates, for whatever reason, the mode
+line of the @samp{*compilation*} buffer changes to say @samp{exit}
+(followed by the exit code, @samp{[0]} for a normal exit), or
address@hidden (if a signal terminated the process), instead of
address@hidden
+
address@hidden kill-compilation
+ Starting a new compilation also kills any compilation already
+running in @samp{*compilation*}, as the buffer can only handle one
+compilation at any time. However, @kbd{M-x compile} asks for
+confirmation before actually killing a compilation that is running.
+You can also kill the compilation process with @kbd{M-x
+kill-compilation}.
+
+ If you want to run two compilations at once, you should start the
+first one, then rename the @samp{*compilation*} buffer (perhaps using
address@hidden; @pxref{Misc Buffer}), and start the other
+compilation. That will create a new @samp{*compilation*} buffer.
+
+ Emacs does not expect a compiler process to launch asynchronous
+subprocesses; if it does, and they keep running after the main
+compiler process has terminated, Emacs may kill them or their output
+may not arrive in Emacs. To avoid this problem, make the main process
+wait for its subprocesses to finish. In a shell script, you can do this
+using @samp{$!} and @samp{wait}, like this:
+
address@hidden
+(sleep 10; echo 2nd)& pid=$! # @r{Record pid of subprocess}
+echo first message
+wait $pid # @r{Wait for subprocess}
address@hidden example
+
+ If the background process does not output to the compilation buffer,
+so you only need to prevent it from being killed when the main
+compilation process terminates, this is sufficient:
+
address@hidden
+nohup @var{command}; sleep 1
address@hidden example
+
address@hidden compilation-environment
+ You can control the environment passed to the compilation command
+with the variable @code{compilation-environment}. Its value is a list
+of environment variable settings; each element should be a string of
+the form @code{"@address@hidden"}. These environment
+variable settings override the usual ones.
+
address@hidden Compilation Mode
address@hidden Compilation Mode
+
address@hidden Compilation mode
address@hidden mode, Compilation
+ The @samp{*compilation*} buffer uses a special major mode,
+Compilation mode, whose main feature is to provide a convenient way to
+visit the source line corresponding to an error message. These
+commands are also available in other special buffers that list
+locations in files, including those made by @kbd{M-x grep} and
address@hidden occur}.
+
address@hidden @kbd
address@hidden M-g M-n
address@hidden M-g n
address@hidden C-x `
+Visit the locus of the next error message or match.
address@hidden M-g M-p
address@hidden M-g p
+Visit the locus of the previous error message or match.
address@hidden @key{RET}
+Visit the locus of the error message that point is on.
+This command is used in the compilation buffer.
address@hidden Mouse-2
+Visit the locus of the error message that you click on.
address@hidden M-n
+Find and highlight the locus of the next error message, without
+selecting the source buffer.
address@hidden M-p
+Find and highlight the locus of the previous error message, without
+selecting the source buffer.
address@hidden address@hidden
+Move point to the next error for a different file than the current
+one.
address@hidden address@hidden
+Move point to the previous error for a different file than the current
+one.
address@hidden C-c C-f
+Toggle Next Error Follow minor mode, which makes cursor motion in the
+compilation buffer produce automatic source display.
address@hidden table
+
address@hidden compile-goto-error
+ You can visit the source for any particular error message by moving
+point in the @samp{*compilation*} buffer to that error message and
+typing @key{RET} (@code{compile-goto-error}). Alternatively, you can
+click @kbd{Mouse-2} on the error message; you need not switch to the
address@hidden buffer first.
+
address@hidden M-g M-n
address@hidden M-g n
address@hidden C-x `
address@hidden next-error
address@hidden next-error-highlight
+ To parse the compiler error messages sequentially, type @kbd{C-x `}
+(@code{next-error}). The character following the @kbd{C-x} is the
+backquote or ``grave accent,'' not the single-quote. This command is
+available in all buffers, not just in @samp{*compilation*}; it
+displays the next error message at the top of one window and source
+location of the error in another window. It also temporarily
+highlights the relevant source line, for a period controlled by the
+variable @code{next-error-highlight}.
+
+ The first time @address@hidden `}} is used after the start of a compilation,
+it moves to the first error's location. Subsequent uses of @kbd{C-x
+`} advance down to subsequent errors. If you visit a specific error
+message with @key{RET} or @kbd{Mouse-2}, subsequent @address@hidden `}}
+commands advance from there. When @address@hidden `}} gets to the end of the
+buffer and finds no more error messages to visit, it fails and signals
+an Emacs error. @address@hidden C-x `}} starts scanning from the beginning of
+the compilation buffer, and goes to the first error's location.
+
address@hidden compilation-skip-threshold
+ By default, @address@hidden `}} skips less important messages. The variable
address@hidden controls this. If its value is 2,
address@hidden@kbd{C-x `}} skips anything less than error, 1 skips anything less
+than warning, and 0 doesn't skip any messages. The default is 1.
+
+ When the window has a left fringe, an arrow in the fringe points to
+the current message in the compilation buffer. The variable
address@hidden controls the number of lines of
+leading context to display before the current message. Going to an
+error message location scrolls the @samp{*compilation*} buffer to put
+the message that far down from the top. The value @code{nil} is
+special: if there's a left fringe, the window doesn't scroll at all
+if the message is already visible. If there is no left fringe,
address@hidden means display the message at the top of the window.
+
+ If you're not in the compilation buffer when you run
address@hidden, Emacs will look for a buffer that contains error
+messages. First, it looks for one displayed in the selected frame,
+then for one that previously had @code{next-error} called on it, and
+then at the current buffer. Finally, Emacs looks at all the remaining
+buffers. @code{next-error} signals an error if it can't find any such
+buffer.
+
address@hidden compilation-error-regexp-alist
address@hidden grep-regexp-alist
+ To parse messages from the compiler, Compilation mode uses the
+variable @code{compilation-error-regexp-alist} which lists various
+formats of error messages and tells Emacs how to extract the source file
+and the line number from the text of a message. If your compiler isn't
+supported, you can tailor Compilation mode to it by adding elements to
+that list. A similar variable @code{grep-regexp-alist} tells Emacs how
+to parse output of a @code{grep} command.
+
address@hidden compilation-next-error
address@hidden compilation-previous-error
address@hidden compilation-next-file
address@hidden compilation-previous-file
+ Compilation mode also redefines the keys @key{SPC} and @key{DEL} to
+scroll by screenfuls, and @kbd{M-n} (@code{compilation-next-error})
+and @kbd{M-p} (@code{compilation-previous-error}) to move to the next
+or previous error message. You can also use @address@hidden
+(@code{compilation-next-file} and @address@hidden
+(@code{compilation-previous-file}) to move up or down to an error
+message for a different source file.
+
address@hidden Next Error Follow mode
address@hidden next-error-follow-minor-mode
+ You can type @kbd{C-c C-f} to toggle Next Error Follow mode. In
+this minor mode, ordinary cursor motion in the compilation buffer
+automatically updates the source buffer. For instance, moving the
+cursor to the next error message causes the location of that error to
+be displayed immediately.
+
+ The features of Compilation mode are also available in a minor mode
+called Compilation Minor mode. This lets you parse error messages in
+any buffer, not just a normal compilation output buffer. Type @kbd{M-x
+compilation-minor-mode} to enable the minor mode. This defines the keys
address@hidden and @kbd{Mouse-2}, as in the Compilation major mode.
+
+ Compilation minor mode works in any buffer, as long as the contents
+are in a format that it understands. In an Rlogin buffer (@pxref{Remote
+Host}), Compilation minor mode automatically accesses remote source
+files by FTP (@pxref{File Names}).
+
address@hidden Compilation Shell
address@hidden Subshells for Compilation
+
+ Emacs uses a shell to run the compilation command, but specifies the
+option for a noninteractive shell. This means, in particular, that
+the shell should start with no prompt. If you find your usual shell
+prompt making an unsightly appearance in the @samp{*compilation*}
+buffer, it means you have made a mistake in your shell's init file by
+setting the prompt unconditionally. (This init file's name may be
address@hidden, @file{.profile}, @file{.cshrc}, @file{.shrc}, or
+various other things, depending on the shell you use.) The shell init
+file should set the prompt only if there already is a prompt. Here's
+how to do it in bash:
+
address@hidden
+if [ "address@hidden@}" = set ]
+then address@hidden
+fi
address@hidden example
+
address@hidden
+And here's how to do it in csh:
+
address@hidden
+if ($?prompt) set prompt = @dots{}
address@hidden example
+
+ There may well be other things that your shell's init file
+ought to do only for an interactive shell. You can use the same
+method to conditionalize them.
+
+ The MS-DOS ``operating system'' does not support asynchronous
+subprocesses; to work around this lack, @kbd{M-x compile} runs the
+compilation command synchronously on MS-DOS. As a consequence, you must
+wait until the command finishes before you can do anything else in
+Emacs.
address@hidden
address@hidden,,emacs-xtra}.
address@hidden iftex
address@hidden
address@hidden
address@hidden ifnottex
+
address@hidden Grep Searching
address@hidden Searching with Grep under Emacs
+
+ Just as you can run a compiler from Emacs and then visit the lines
+with compilation errors, you can also run @code{grep} and then visit
+the lines on which matches were found. This works by treating the
+matches reported by @code{grep} as if they were ``errors.'' The
+buffer of matches uses Grep mode, which is a variant of Compilation
+mode (@pxref{Compilation Mode}).
+
address@hidden @kbd
address@hidden M-x grep
address@hidden M-x lgrep
+Run @code{grep} asynchronously under Emacs, with matching lines
+listed in the buffer named @samp{*grep*}.
address@hidden M-x grep-find
address@hidden M-x find-grep
address@hidden M-x rgrep
+Run @code{grep} via @code{find}, with user-specified arguments, and
+collect output in the buffer named @samp{*grep*}.
address@hidden M-x kill-grep
+Kill the running @code{grep} subprocess.
address@hidden table
+
address@hidden grep
+ To run @code{grep}, type @kbd{M-x grep}, then enter a command line
+that specifies how to run @code{grep}. Use the same arguments you
+would give @code{grep} when running it normally: a @code{grep}-style
+regexp (usually in single-quotes to quote the shell's special
+characters) followed by file names, which may use wildcards. If you
+specify a prefix argument for @kbd{M-x grep}, it finds the tag
+(@pxref{Tags}) in the buffer around point, and puts that into the
+default @code{grep} command.
+
+ Your command need not simply run @code{grep}; you can use any shell
+command that produces output in the same format. For instance, you
+can chain @code{grep} commands, like this:
+
address@hidden
+grep -nH -e foo *.el | grep bar | grep toto
address@hidden example
+
+ The output from @code{grep} goes in the @samp{*grep*} buffer. You
+can find the corresponding lines in the original files using @address@hidden
+`}}, @key{RET}, and so forth, just like compilation errors.
+
+ Some grep programs accept a @samp{--color} option to output special
+markers around matches for the purpose of highlighting. You can make
+use of this feature by setting @code{grep-highlight-matches} to
address@hidden When displaying a match in the source buffer, the exact
+match will be highlighted, instead of the entire source line.
+
address@hidden grep-find
address@hidden find-grep
+ The command @kbd{M-x grep-find} (also available as @kbd{M-x
+find-grep}) is similar to @kbd{M-x grep}, but it supplies a different
+initial default for the command---one that runs both @code{find} and
address@hidden, so as to search every file in a directory tree. See also
+the @code{find-grep-dired} command, in @ref{Dired and Find}.
+
address@hidden lgrep
address@hidden rgrep
+ The commands @kbd{M-x lgrep} (local grep) and @kbd{M-x rgrep}
+(recursive grep) are more user-friendly versions of @code{grep} and
address@hidden, which prompt separately for the regular expression
+to match, the files to search, and the base directory for the search.
+Case sensitivity of the search is controlled by the
+current value of @code{case-fold-search}.
+
+These commands build the shell commands based on the variables
address@hidden (for @code{lgrep}) and @code{grep-find-template}
+(for @code{rgrep}).
+
+The files to search can use aliases defined in the variable
address@hidden
+
+Subdirectories listed in the variable
address@hidden such as those typically used by
+various version control systems, like CVS and arch, are automatically
+skipped by @code{rgrep}.
+
address@hidden Flymake
address@hidden Finding Syntax Errors On The Fly
address@hidden checking syntax
+
+ Flymake mode is a minor mode that performs on-the-fly syntax
+checking for many programming and markup languages, including C, C++,
+Perl, HTML, and @TeX{}/address@hidden It is somewhat analogous to Flyspell
+mode, which performs spell checking for ordinary human languages in a
+similar fashion (@pxref{Spelling}). As you edit a file, Flymake mode
+runs an appropriate syntax checking tool in the background, using a
+temporary copy of the buffer. It then parses the error and warning
+messages, and highlights the erroneous lines in the buffer. The
+syntax checking tool used depends on the language; for example, for
+C/C++ files this is usually the C compiler. Flymake can also use
+build tools such as @code{make} for checking complicated projects.
+
+ To activate Flymake mode, type @kbd{M-x flymake-mode}. You can move
+to the errors spotted by Flymake mode with @kbd{M-x
+flymake-goto-next-error} and @kbd{M-x flymake-goto-prev-error}. To
+display any error messages associated with the current line, use
address@hidden flymake-display-err-menu-for-current-line}.
+
+ For more details about using Flymake, see @ref{Top, Flymake,
+Flymake, flymake, The Flymake Manual}.
+
address@hidden Debuggers
address@hidden Running Debuggers Under Emacs
address@hidden debuggers
address@hidden GUD library
address@hidden GDB
address@hidden DBX
address@hidden SDB
address@hidden XDB
address@hidden Perldb
address@hidden JDB
address@hidden PDB
+
address@hidden Do you believe in GUD?
+The GUD (Grand Unified Debugger) library provides an interface to
+various symbolic debuggers from within Emacs. We recommend the
+debugger GDB, which is free software, but GUD can also run DBX, SDB or
+XDB. GUD can also serve as an interface to Perl's debugging mode, the
+Python debugger PDB, and to JDB, the Java Debugger.
address@hidden,, The Lisp Debugger, elisp, the Emacs Lisp Reference
+Manual}, for information on debugging Emacs Lisp programs.
+
address@hidden
+* Starting GUD:: How to start a debugger subprocess.
+* Debugger Operation:: Connection between the debugger and source buffers.
+* Commands of GUD:: Key bindings for common commands.
+* GUD Customization:: Defining your own commands for GUD.
+* GDB Graphical Interface:: An enhanced mode that uses GDB features to
+ implement a graphical debugging environment through
+ Emacs.
address@hidden menu
+
address@hidden Starting GUD
address@hidden Starting GUD
+
+ There are several commands for starting a debugger, each corresponding
+to a particular debugger program.
+
address@hidden @kbd
address@hidden M-x gdb @key{RET} @var{file} @key{RET}
address@hidden gdb
+Run GDB as a subprocess of Emacs. By default, this uses an IDE-like
+graphical interface; see @ref{GDB Graphical Interface}. Only GDB
+works with the graphical interface.
+
address@hidden M-x dbx @key{RET} @var{file} @key{RET}
address@hidden dbx
+Run DBX as a subprocess of Emacs. Since Emacs does not implement a
+graphical interface for DBX, communication with DBX works by typing
+commands in the GUD interaction buffer. The same is true for all
+the other supported debuggers.
+
address@hidden M-x xdb @key{RET} @var{file} @key{RET}
address@hidden xdb
address@hidden gud-xdb-directories
+Similar, but run XDB. Use the variable
address@hidden to specify directories to search for source
+files.
+
address@hidden M-x sdb @key{RET} @var{file} @key{RET}
address@hidden sdb
+Similar, but run SDB.
+
+ Some versions of SDB do not mention source file names in their
+messages. When you use them, you need to have a valid tags table
+(@pxref{Tags}) in order for GUD to find functions in the source code.
+If you have not visited a tags table or the tags table doesn't list one
+of the functions, you get a message saying @samp{The sdb support
+requires a valid tags table to work}. If this happens, generate a valid
+tags table in the working directory and try again.
+
address@hidden M-x perldb @key{RET} @var{file} @key{RET}
address@hidden perldb
+Run the Perl interpreter in debug mode to debug @var{file}, a Perl program.
+
address@hidden M-x jdb @key{RET} @var{file} @key{RET}
address@hidden jdb
+Run the Java debugger to debug @var{file}.
+
address@hidden M-x pdb @key{RET} @var{file} @key{RET}
address@hidden pdb
+Run the Python debugger to debug @var{file}.
address@hidden table
+
+ Each of these commands takes one argument: a command line to invoke
+the debugger. In the simplest case, specify just the name of the
+executable file you want to debug. You may also use options that the
+debugger supports. However, shell wildcards and variables are not
+allowed. GUD assumes that the first argument not starting with a
address@hidden is the executable file name.
+
+Tramp provides a facility to debug programs on remote hosts.
address@hidden a debugger on a remote host, Running a debugger on a remote
host,, tramp, The Tramp Manual}.
address@hidden Running a debugger on a remote host
+
address@hidden Debugger Operation
address@hidden Debugger Operation
+
address@hidden fringes, and current execution line in GUD
+ Generally when you run a debugger with GUD, the debugger uses an Emacs
+buffer for its ordinary input and output. This is called the GUD
+buffer. Input and output from the program you are debugging also use
+this buffer. We call this @dfn{text command mode}. The GDB Graphical
+Interface can use further buffers (@pxref{GDB Graphical Interface}).
+
+ The debugger displays the source files of the program by visiting
+them in Emacs buffers. An arrow in the left fringe indicates the
+current execution address@hidden a text-only terminal, the arrow
+appears as @samp{=>} and overlays the first two text columns.} Moving
+point in this buffer does not move the arrow. The arrow is not part
+of the file's text; it appears only on the screen.
+
+ You can start editing these source files at any time in the buffers
+that display them. If you do modify a source file, keep in mind that
+inserting or deleting lines will throw off the arrow's positioning;
+GUD has no way of figuring out which line corresponded before your
+changes to the line number in a debugger message. Also, you'll
+typically have to recompile and restart the program for your changes
+to be reflected in the debugger's tables.
+
address@hidden tooltips with GUD
address@hidden tooltip-gud-modes
address@hidden gud-tooltip-mode
address@hidden gud-tooltip-echo-area
+ The Tooltip facility (@pxref{Tooltips}) provides support for address@hidden
+You activate this feature by turning on the minor mode
address@hidden Then you can display a variable's value in a
+tooltip simply by pointing at it with the mouse. This operates in the
+GUD buffer and in source buffers with major modes in the list
address@hidden If the variable @code{gud-tooltip-echo-area}
+is address@hidden then the variable's value is displayed in the echo
+area. When debugging a C program using the GDB Graphical Interface, you
+can also display macro definitions associated with an identifier when
+the program is not executing.
+
+ GUD tooltips are disabled when you use GDB in text command mode
+(@pxref{GDB Graphical Interface}), because displaying an expression's
+value in GDB can sometimes expand a macro and result in a side effect
+that interferes with the program's operation. The GDB graphical
+interface supports GUD tooltips and assures they will not cause side
+effects.
+
address@hidden Commands of GUD
address@hidden Commands of GUD
+
+ The GUD interaction buffer uses a variant of Shell mode, so the
+Emacs commands of Shell mode are available (@pxref{Shell Mode}). All
+the usual commands for your debugger are available, and you can use
+the Shell mode history commands to repeat them. If you wish, you can
+control your debugger process entirely through this buffer.
+
+ GUD mode also provides commands for setting and clearing
+breakpoints, for selecting stack frames, and for stepping through the
+program. These commands are available both in the GUD buffer and
+globally, but with different key bindings. It also has its own tool
+bar from which you can invoke the more common commands by clicking on
+the appropriate icon. This is particularly useful for repetitive
+commands like @code{gud-next} and @code{gud-step}, and allows you to
+keep the GUD buffer hidden.
+
+ The breakpoint commands are normally used in source file buffers,
+because that is the easiest way to specify where to set or clear the
+breakpoint. Here's the global command to set a breakpoint:
+
address@hidden @kbd
address@hidden C-x @key{SPC}
address@hidden C-x SPC
+Set a breakpoint on the source line that point is on.
address@hidden table
+
address@hidden C-x C-a @r{(GUD)}
+ Here are the other special commands provided by address@hidden The keys
+starting with @kbd{C-c} are available only in the GUD interaction
+buffer. The key bindings that start with @kbd{C-x C-a} are available
+in the GUD interaction buffer and also in source files. Some of these
+commands are not available to all the supported debuggers.
+
address@hidden @kbd
address@hidden C-c C-l
address@hidden C-c C-l @r{(GUD)}
address@hidden C-x C-a C-l
address@hidden gud-refresh
+Display in another window the last line referred to in the GUD
+buffer (that is, the line indicated in the last location message).
+This runs the command @code{gud-refresh}.
+
address@hidden C-c C-s
address@hidden C-c C-s @r{(GUD)}
address@hidden C-x C-a C-s
address@hidden gud-step
+Execute a single line of code (@code{gud-step}). If the line contains
+a function call, execution stops after entering the called function.
+
address@hidden C-c C-n
address@hidden C-c C-n @r{(GUD)}
address@hidden C-x C-a C-n
address@hidden gud-next
+Execute a single line of code, stepping across entire function calls
+at full speed (@code{gud-next}).
+
address@hidden C-c C-i
address@hidden C-c C-i @r{(GUD)}
address@hidden C-x C-a C-i
address@hidden gud-stepi
+Execute a single machine instruction (@code{gud-stepi}).
+
address@hidden C-c C-p
address@hidden C-c C-p @r{(GUD)}
address@hidden C-x C-a C-p
address@hidden gud-print
+Evaluate the expression at point (@code{gud-print}). If Emacs
+does not print the exact expression that you want, mark it as a region
+first.
+
address@hidden 3000
address@hidden C-c C-r
address@hidden C-c C-r @r{(GUD)}
address@hidden C-x C-a C-r
address@hidden gud-cont
+Continue execution without specifying any stopping point. The program
+will run until it hits a breakpoint, terminates, or gets a signal that
+the debugger is checking for (@code{gud-cont}).
+
address@hidden 1000
address@hidden C-c C-d
address@hidden C-c C-d @r{(GUD)}
address@hidden C-x C-a C-d
address@hidden gud-remove
+Delete the breakpoint(s) on the current source line, if any
+(@code{gud-remove}). If you use this command in the GUD interaction
+buffer, it applies to the line where the program last stopped.
+
address@hidden C-c C-t
address@hidden C-c C-t @r{(GUD)}
address@hidden C-x C-a C-t
address@hidden gud-tbreak
+Set a temporary breakpoint on the current source line, if any
+(@code{gud-tbreak}). If you use this command in the GUD interaction
+buffer, it applies to the line where the program last stopped.
+
address@hidden C-c <
address@hidden C-c < @r{(GUD)}
address@hidden C-x C-a <
address@hidden gud-up
+Select the next enclosing stack frame (@code{gud-up}). This is
+equivalent to the GDB command @samp{up}.
+
address@hidden C-c >
address@hidden C-c > @r{(GUD)}
address@hidden C-x C-a >
address@hidden gud-down
+Select the next inner stack frame (@code{gud-down}). This is
+equivalent to the GDB command @samp{down}.
+
address@hidden C-c C-u
address@hidden C-c C-u @r{(GUD)}
address@hidden C-x C-a C-u
address@hidden gud-until
+Continue execution to the current line (@code{gud-until}). The
+program will run until it hits a breakpoint, terminates, gets a signal
+that the debugger is checking for, or reaches the line on which the
+cursor currently sits.
+
address@hidden C-c C-f
address@hidden C-c C-f @r{(GUD)}
address@hidden C-x C-a C-f
address@hidden gud-finish
+Run the program until the selected stack frame returns or
+stops for some other reason (@code{gud-finish}).
address@hidden table
+
+ If you are using GDB, these additional key bindings are available:
+
address@hidden @kbd
address@hidden C-x C-a C-j
address@hidden C-x C-a C-j @r{(GUD)}
address@hidden gud-jump
+Only useful in a source buffer, @code{gud-jump} transfers the
+program's execution point to the current line. In other words, the
+next line that the program executes will be the one where you gave the
+command. If the new execution line is in a different function from
+the previously one, GDB prompts for confirmation since the results may
+be bizarre. See the GDB manual entry regarding @code{jump} for
+details.
+
address@hidden @key{TAB}
address@hidden TAB @r{(GUD)}
address@hidden gud-gdb-complete-command
+With GDB, complete a symbol name (@code{gud-gdb-complete-command}).
+This key is available only in the GUD interaction buffer.
address@hidden table
+
+ These commands interpret a numeric argument as a repeat count, when
+that makes sense.
+
+ Because @key{TAB} serves as a completion command, you can't use it to
+enter a tab as input to the program you are debugging with GDB.
+Instead, type @kbd{C-q @key{TAB}} to enter a tab.
+
address@hidden GUD Customization
address@hidden GUD Customization
+
address@hidden gdb-mode-hook
address@hidden dbx-mode-hook
address@hidden sdb-mode-hook
address@hidden xdb-mode-hook
address@hidden perldb-mode-hook
address@hidden pdb-mode-hook
address@hidden jdb-mode-hook
+ On startup, GUD runs one of the following hooks: @code{gdb-mode-hook},
+if you are using GDB; @code{dbx-mode-hook}, if you are using DBX;
address@hidden, if you are using SDB; @code{xdb-mode-hook}, if you
+are using XDB; @code{perldb-mode-hook}, for Perl debugging mode;
address@hidden, for PDB; @code{jdb-mode-hook}, for JDB. You can
+use these hooks to define custom key bindings for the debugger
+interaction buffer. @xref{Hooks}.
+
+ Here is a convenient way to define a command that sends a particular
+command string to the debugger, and set up a key binding for it in the
+debugger interaction buffer:
+
address@hidden gud-def
address@hidden
+(gud-def @var{function} @var{cmdstring} @var{binding} @var{docstring})
address@hidden example
+
+ This defines a command named @var{function} which sends
address@hidden to the debugger process, and gives it the documentation
+string @var{docstring}. You can then use the command @var{function} in any
+buffer. If @var{binding} is address@hidden, @code{gud-def} also binds
+the command to @kbd{C-c @var{binding}} in the GUD buffer's mode and to
address@hidden C-a @var{binding}} generally.
+
+ The command string @var{cmdstring} may contain certain
address@hidden that stand for data to be filled in at the time
address@hidden is called:
+
address@hidden @samp
address@hidden %f
+The name of the current source file. If the current buffer is the GUD
+buffer, then the ``current source file'' is the file that the program
+stopped in.
+
address@hidden %l
+The number of the current source line. If the current buffer is the GUD
+buffer, then the ``current source line'' is the line that the program
+stopped in.
+
address@hidden %e
+In transient-mark-mode the text in the region, if it is active.
+Otherwise the text of the C lvalue or function-call expression at or
+adjacent to point.
+
address@hidden %a
+The text of the hexadecimal address at or adjacent to point.
+
address@hidden %p
+The numeric argument of the called function, as a decimal number. If
+the command is used without a numeric argument, @samp{%p} stands for the
+empty string.
+
+If you don't use @samp{%p} in the command string, the command you define
+ignores any numeric argument.
+
address@hidden %d
+The name of the directory of the current source file.
+
address@hidden %c
+Fully qualified class name derived from the expression surrounding point
+(jdb only).
address@hidden table
+
address@hidden GDB Graphical Interface
address@hidden GDB Graphical Interface
+
+ By default, the command @code{gdb} starts GDB using a graphical
+interface, using Emacs windows for display program state information.
+In effect, this makes Emacs into an IDE (interactive development
+environment). With it, you do not need to use textual GDB commands;
+you can control the debugging session with the mouse. For example,
+you can click in the fringe of a source buffer to set a breakpoint
+there, or on a stack frame in the stack buffer to select that frame.
+
+ This mode requires telling GDB that its ``screen size'' is
+unlimited, so it sets the height and width accordingly. For correct
+operation you must not change these values during the GDB session.
+
address@hidden gud-gdb-command-name
address@hidden gdba
+ You can also run GDB in text command mode, like other debuggers. To
+do this, replace the GDB @code{"--annotate=3"} option with
address@hidden"--fullname"} either in the minibuffer for the current Emacs
+session, or the custom variable @code{gud-gdb-command-name} for all
+future sessions. You need to use text command mode to debug multiple
+programs within one Emacs session. If you have customized
address@hidden in this way, you can use @kbd{M-x gdba} to
+invoke GDB in graphical mode. Moreover, this command succeeds where
address@hidden gdb} fails, such as when your @file{.gdbinit} file contains
+executable GDB commands.
+
address@hidden
+* GDB-UI Layout:: Control the number of displayed buffers.
+* Source Buffers:: Use the mouse in the fringe/margin to
+ control your program.
+* Breakpoints Buffer:: A breakpoint control panel.
+* Stack Buffer:: Select a frame from the call stack.
+* Other GDB-UI Buffers:: Input/output, locals, registers,
+ assembler, threads and memory buffers.
+* Watch Expressions:: Monitor variable values in the speedbar.
address@hidden menu
+
address@hidden GDB-UI Layout
address@hidden GDB User Interface Layout
address@hidden GDB User Interface layout
+
address@hidden gdb-many-windows
+ If the variable @code{gdb-many-windows} is @code{nil} (the default
+value) then @kbd{M-x gdb} normally displays only the GUD buffer.
+However, if the variable @code{gdb-show-main} is also address@hidden,
+it starts with two windows: one displaying the GUD buffer, and the
+other showing the source for the @code{main} function of the program
+you are debugging.
+
+ If @code{gdb-many-windows} is address@hidden, then @kbd{M-x gdb}
+displays the following frame layout:
+
address@hidden
address@hidden
++--------------------------------+--------------------------------+
+| GUD buffer (I/O of GDB) | Locals buffer |
+|--------------------------------+--------------------------------+
+| Primary Source buffer | I/O buffer for debugged pgm |
+|--------------------------------+--------------------------------+
+| Stack buffer | Breakpoints buffer |
++--------------------------------+--------------------------------+
address@hidden group
address@hidden smallexample
+
+ However, if @code{gdb-use-separate-io-buffer} is @code{nil}, the I/O
+buffer does not appear and the primary source buffer occupies the full
+width of the frame.
+
address@hidden gdb-restore-windows
+ If you change the window layout, for example, while editing and
+re-compiling your program, then you can restore this standard window
+layout with the command @code{gdb-restore-windows}.
+
address@hidden gdb-many-windows
+ To switch between this standard layout and a simple layout
+containing just the GUD buffer and a source file, type @kbd{M-x
+gdb-many-windows}.
+
+ You may also specify additional GDB-related buffers to display,
+either in the same frame or a different one. Select the buffers you
+want with the @samp{GUD->GDB-windows} and @samp{GUD->GDB-Frames}
+sub-menus. If the menu-bar is unavailable, type @code{M-x
address@hidden or @code{M-x
address@hidden respectively, where
address@hidden is the relevant buffer type, such as
address@hidden Most of these buffers are read-only, and typing
address@hidden in them kills them.
+
+ When you finish debugging, kill the GUD buffer with @kbd{C-x k},
+which will also kill all the buffers associated with the session.
+However you need not do this if, after editing and re-compiling your
+source code within Emacs, you wish continue debugging. When you
+restart execution, GDB will automatically find your new executable.
+Keeping the GUD buffer has the advantage of keeping the shell history
+as well as GDB's breakpoints. You do need to check that the
+breakpoints in recently edited source files are still in the right
+places.
+
address@hidden Source Buffers
address@hidden Source Buffers
address@hidden GDB commands in Fringe
+
address@hidden @findex gdb-mouse-set-clear-breakpoint
address@hidden @findex gdb-mouse-toggle-breakpoint
+Many GDB commands can be entered using keybindings or the tool bar but
+sometimes it is quicker to use the fringe. These commands either
+manipulate breakpoints or control program execution. When there is no
+fringe, you can use the margin but this is only present when the
+source file already has a breakpoint.
+
+You can click @kbd{Mouse-1} in the fringe or display margin of a
+source buffer to set a breakpoint there and, on a graphical display, a
+red bullet will appear on that line. If a breakpoint already exists
+on that line, the same click will remove it. You can also enable or
+disable a breakpoint by clicking @kbd{C-Mouse-1} on the bullet.
+
+A solid arrow in the left fringe of a source buffer indicates the line
+of the innermost frame where the debugged program has stopped. A
+hollow arrow indicates the current execution line of higher level
+frames.
+
+If you drag the arrow in the fringe with @kbd{Mouse-1}
+(@code{gdb-mouse-until}), execution will continue to the line where
+you release the button, provided it is still in the same frame.
+Alternatively, you can click @kbd{Mouse-3} at some point in the fringe
+of this buffer and execution will advance to there. A similar command
+(@code{gdb-mouse-jump}) allows you to jump to a source line without
+executing the intermediate lines by clicking @kbd{C-Mouse-3}. This
+command allows you to go backwards which can be useful for running
+through code that has already executed, in order to examine its
+execution in more detail.
+
address@hidden @kbd
address@hidden Mouse-1
+Set or clear a breakpoint.
+
address@hidden C-Mouse-1
+Enable or disable a breakpoint.
+
address@hidden Mouse-3
+Continue execution to here.
+
address@hidden C-Mouse-3
+Jump to here.
address@hidden table
+
+If the variable @code{gdb-find-source-frame} is address@hidden and
+execution stops in a frame for which there is no source code e.g after
+an interrupt, then Emacs finds and displays the first frame further up
+stack for which there is source. If it is @code{nil} then the source
+buffer continues to display the last frame which maybe more useful,
+for example, when re-setting a breakpoint.
+
address@hidden Breakpoints Buffer
address@hidden Breakpoints Buffer
+
+ The breakpoints buffer shows the existing breakpoints, watchpoints and
+catchpoints (@pxref{Breakpoints,,, gdb, The GNU debugger}). It has
+these special commands, which mostly apply to the @dfn{current
+breakpoint}, the breakpoint which point is on.
+
address@hidden @kbd
address@hidden @key{SPC}
address@hidden SPC @r{(GDB breakpoints buffer)}
address@hidden gdb-toggle-breakpoint
+Enable/disable the current breakpoint (@code{gdb-toggle-breakpoint}).
+On a graphical display, this changes the color of a bullet in the
+margin of a source buffer at the relevant line. This is red when
+the breakpoint is enabled and grey when it is disabled. Text-only
+terminals correspondingly display a @samp{B} or @samp{b}.
+
address@hidden D
address@hidden D @r{(GDB breakpoints buffer)}
address@hidden gdb-delete-breakpoint
+Delete the current breakpoint (@code{gdb-delete-breakpoint}).
+
address@hidden @key{RET}
address@hidden RET @r{(GDB breakpoints buffer)}
address@hidden gdb-goto-breakpoint
+Visit the source line for the current breakpoint
+(@code{gdb-goto-breakpoint}).
+
address@hidden Mouse-2
address@hidden Mouse-2 @r{(GDB breakpoints buffer)}
+Visit the source line for the breakpoint you click on.
address@hidden table
+
address@hidden Stack Buffer
address@hidden Stack Buffer
+
+ The stack buffer displays a @dfn{call stack}, with one line for each
+of the nested subroutine calls (@dfn{stack frames}) now active in the
+program. @xref{Backtrace,, Backtraces, gdb, The GNU debugger}.
+
address@hidden gdb-frames-select
+An arrow in the fringe points to the selected frame or, if the fringe is
+not present, the number of the selected frame is displayed in reverse
+contrast. To select a frame in GDB, move point in the stack buffer to
+that stack frame and type @key{RET} (@code{gdb-frames-select}), or click
address@hidden on a stack frame. If the locals buffer is visible,
+selecting a stack frame updates it to display the local variables of the
+new frame.
+
address@hidden Other GDB-UI Buffers
address@hidden Other Buffers
+
address@hidden @asis
address@hidden Input/Output Buffer
address@hidden gdb-use-separate-io-buffer
+If the variable @code{gdb-use-separate-io-buffer} is address@hidden,
+the program being debugged takes its input and displays its output
+here. Otherwise it uses the GUD buffer for that. To toggle whether
+GUD mode uses this buffer, do @kbd{M-x gdb-use-separate-io-buffer}.
+This takes effect when you next restart the program you are debugging.
+
+The history and replay commands from Shell mode are available here,
+as are the commands to send signals to the debugged program.
address@hidden Mode}.
+
address@hidden Locals Buffer
+The locals buffer displays the values of local variables of the
+current frame for simple data types (@pxref{Frame Info, Frame Info,
+Information on a frame, gdb, The GNU debugger}). Press @key{RET} or
+click @kbd{Mouse-2} on the value if you want to edit it.
+
+Arrays and structures display their type only. With GDB 6.4 or later,
+move point to their name and press @key{RET}, or alternatively click
address@hidden there, to examine their values. With earlier versions
+of GDB, use @kbd{Mouse-2} or @key{RET} on the type description
+(@samp{[struct/union]} or @samp{[array]}). @xref{Watch Expressions}.
+
address@hidden Registers Buffer
address@hidden toggle-gdb-all-registers
+The registers buffer displays the values held by the registers
+(@pxref{Registers,,, gdb, The GNU debugger}). Press @key{RET} or
+click @kbd{Mouse-2} on a register if you want to edit its value.
+With GDB 6.4 or later, recently changed register values display with
address@hidden With earlier versions of GDB, you can
+press @key{SPC} to toggle the display of floating point registers
+(@code{toggle-gdb-all-registers}).
+
address@hidden Assembler Buffer
+The assembler buffer displays the current frame as machine code. An
+arrow points to the current instruction, and you can set and remove
+breakpoints as in a source buffer. Breakpoint icons also appear in
+the fringe or margin.
+
address@hidden Threads Buffer
address@hidden gdb-threads-select
+The threads buffer displays a summary of all threads currently in your
+program (@pxref{Threads, Threads, Debugging programs with multiple
+threads, gdb, The GNU debugger}). Move point to any thread in the
+list and press @key{RET} to select it (@code{gdb-threads-select}) and
+display the associated source in the primary source buffer.
+Alternatively, click @kbd{Mouse-2} on a thread to select it. If the
+locals buffer is visible, its contents update to display the variables
+that are local in the new thread.
+
address@hidden Memory Buffer
+The memory buffer lets you examine sections of program memory
+(@pxref{Memory, Memory, Examining memory, gdb, The GNU debugger}).
+Click @kbd{Mouse-1} on the appropriate part of the header line to
+change the starting address or number of data items that the buffer
+displays. Click @kbd{Mouse-3} on the header line to select the
+display format or unit size for these data items.
address@hidden table
+
address@hidden Watch Expressions
address@hidden Watch Expressions
address@hidden Watching expressions in GDB
+
address@hidden gud-watch
address@hidden C-x C-a C-w @r{(GUD)}
+ If you want to see how a variable changes each time your program
+stops, move point into the variable name and click on the watch icon
+in the tool bar (@code{gud-watch}) or type @kbd{C-x C-a C-w}. If you
+specify a prefix argument, you can enter the variable name in the
+minibuffer.
+
+ Each watch expression is displayed in the speedbar. Complex data
+types, such as arrays, structures and unions are represented in a tree
+format. Leaves and simple data types show the name of the expression
+and its value and, when the speedbar frame is selected, display the
+type as a tooltip. Higher levels show the name, type and address
+value for pointers and just the name and type otherwise. Root expressions
+also display the frame address as a tooltip to help identify the frame
+in which they were defined.
+
+ To expand or contract a complex data type, click @kbd{Mouse-2} or
+press @key{SPC} on the tag to the left of the expression. Emacs asks
+for confirmation before expanding the expression if its number of
+immediate children exceeds the value of the variable
address@hidden
+
address@hidden D @r{(GDB speedbar)}
address@hidden gdb-var-delete
+ To delete a complex watch expression, move point to the root
+expression in the speedbar and type @kbd{D} (@code{gdb-var-delete}).
+
address@hidden RET @r{(GDB speedbar)}
address@hidden gdb-edit-value
+ To edit a variable with a simple data type, or a simple element of a
+complex data type, move point there in the speedbar and type @key{RET}
+(@code{gdb-edit-value}). Or you can click @kbd{Mouse-2} on a value to
+edit it. Either way, this reads the new value using the minibuffer.
+
address@hidden gdb-show-changed-values
+ If you set the variable @code{gdb-show-changed-values} to
address@hidden (the default value), Emacs uses
address@hidden to highlight values that have recently
+changed and @code{shadow} face to make variables which have gone out of
+scope less noticeable. When a variable goes out of scope you can't
+edit its value.
+
address@hidden gdb-use-colon-colon-notation
+ If the variable @code{gdb-use-colon-colon-notation} is
address@hidden, Emacs uses the @address@hidden::@var{variable}}
+format. This allows the user to display watch expressions which share
+the same variable name. The default value is @code{nil}.
+
address@hidden gdb-speedbar-auto-raise
+To automatically raise the speedbar every time the display of watch
+expressions updates, set @code{gdb-speedbar-auto-raise} to
address@hidden This can be useful if you are debugging with a full
+screen Emacs frame.
+
address@hidden Executing Lisp
address@hidden Executing Lisp Expressions
+
+ Emacs has several different major modes for Lisp and Scheme. They are
+the same in terms of editing commands, but differ in the commands for
+executing Lisp expressions. Each mode has its own purpose.
+
address@hidden @asis
address@hidden Emacs-Lisp mode
+The mode for editing source files of programs to run in Emacs Lisp.
+This mode defines @kbd{C-M-x} to evaluate the current defun.
address@hidden Libraries}.
address@hidden Lisp Interaction mode
+The mode for an interactive session with Emacs Lisp. It defines
address@hidden to evaluate the sexp before point and insert its value in the
+buffer. @xref{Lisp Interaction}.
address@hidden Lisp mode
+The mode for editing source files of programs that run in Lisps other
+than Emacs Lisp. This mode defines @kbd{C-M-x} to send the current defun
+to an inferior Lisp process. @xref{External Lisp}.
address@hidden Inferior Lisp mode
+The mode for an interactive session with an inferior Lisp process.
+This mode combines the special features of Lisp mode and Shell mode
+(@pxref{Shell Mode}).
address@hidden Scheme mode
+Like Lisp mode but for Scheme programs.
address@hidden Inferior Scheme mode
+The mode for an interactive session with an inferior Scheme process.
address@hidden table
+
+ Most editing commands for working with Lisp programs are in fact
+available globally. @xref{Programs}.
+
address@hidden Lisp Libraries
address@hidden Libraries of Lisp Code for Emacs
address@hidden libraries
address@hidden loading Lisp code
+
+ Lisp code for Emacs editing commands is stored in files whose names
+conventionally end in @file{.el}. This ending tells Emacs to edit them in
+Emacs-Lisp mode (@pxref{Executing Lisp}).
+
address@hidden byte code
+ Emacs Lisp code can be compiled into byte-code, which loads faster,
+takes up less space, and executes faster. @xref{Byte Compilation,,
+Byte Compilation, elisp, the Emacs Lisp Reference Manual}. By
+convention, the compiled code for a library goes in a separate file
+whose name ends in @samp{.elc}. Thus, the compiled code for
address@hidden goes in @file{foo.elc}.
+
address@hidden load-file
+ To execute a file of Emacs Lisp code, use @kbd{M-x load-file}. This
+command reads a file name using the minibuffer and then executes the
+contents of that file as Lisp code. It is not necessary to visit the
+file first; in any case, this command reads the file as found on disk,
+not text in an Emacs buffer.
+
address@hidden load
address@hidden load-library
+ Once a file of Lisp code is installed in the Emacs Lisp library
+directories, users can load it using @kbd{M-x load-library}. Programs
+can load it by calling @code{load}, a more primitive function that is
+similar but accepts some additional arguments.
+
+ @kbd{M-x load-library} differs from @kbd{M-x load-file} in that it
+searches a sequence of directories and tries three file names in each
+directory. Suppose your argument is @var{lib}; the three names are
address@hidden@var{lib}.elc}, @address@hidden, and lastly just
address@hidden@var{lib}}. If @address@hidden exists, it is by convention
+the result of compiling @address@hidden; it is better to load the
+compiled file, since it will load and run faster.
+
+ If @code{load-library} finds that @address@hidden is newer than
address@hidden@var{lib}.elc} file, it issues a warning, because it's likely
+that somebody made changes to the @file{.el} file and forgot to
+recompile it. Nonetheless, it loads @address@hidden This is
+because people often leave unfinished edits the source file, and don't
+recompile it until they think it is ready to use.
+
+ Because the argument to @code{load-library} is usually not in itself
+a valid file name, file name completion is not available. Indeed, when
+using this command, you usually do not know exactly what file name
+will be used.
+
address@hidden load-path
+ The sequence of directories searched by @kbd{M-x load-library} is
+specified by the variable @code{load-path}, a list of strings that are
+directory names. The default value of the list contains the directories where
+the Lisp code for Emacs itself is stored. If you have libraries of
+your own, put them in a single directory and add that directory
+to @code{load-path}. @code{nil} in this list stands for the current default
+directory, but it is probably not a good idea to put @code{nil} in the
+list. If you find yourself wishing that @code{nil} were in the list,
+most likely what you really want to do is use @kbd{M-x load-file}
+this once.
+
address@hidden autoload
+ Often you do not have to give any command to load a library, because
+the commands defined in the library are set up to @dfn{autoload} that
+library. Trying to run any of those commands calls @code{load} to load
+the library; this replaces the autoload definitions with the real ones
+from the library.
+
address@hidden load-dangerous-libraries
address@hidden Lisp files byte-compiled by XEmacs
+ By default, Emacs refuses to load compiled Lisp files which were
+compiled with XEmacs, a modified versions of Emacs---they can cause
+Emacs to crash. Set the variable @code{load-dangerous-libraries} to
address@hidden if you want to try loading them.
+
address@hidden Lisp Eval
address@hidden Evaluating Emacs Lisp Expressions
address@hidden Emacs-Lisp mode
address@hidden mode, Emacs-Lisp
+
address@hidden emacs-lisp-mode
+ Lisp programs intended to be run in Emacs should be edited in
+Emacs-Lisp mode; this happens automatically for file names ending in
address@hidden By contrast, Lisp mode itself is used for editing Lisp
+programs intended for other Lisp systems. To switch to Emacs-Lisp mode
+explicitly, use the command @kbd{M-x emacs-lisp-mode}.
+
+ For testing of Lisp programs to run in Emacs, it is often useful to
+evaluate part of the program as it is found in the Emacs buffer. For
+example, after changing the text of a Lisp function definition,
+evaluating the definition installs the change for future calls to the
+function. Evaluation of Lisp expressions is also useful in any kind of
+editing, for invoking noninteractive functions (functions that are
+not commands).
+
address@hidden @kbd
address@hidden M-:
+Read a single Lisp expression in the minibuffer, evaluate it, and print
+the value in the echo area (@code{eval-expression}).
address@hidden C-x C-e
+Evaluate the Lisp expression before point, and print the value in the
+echo area (@code{eval-last-sexp}).
address@hidden C-M-x
+Evaluate the defun containing or after point, and print the value in
+the echo area (@code{eval-defun}).
address@hidden M-x eval-region
+Evaluate all the Lisp expressions in the region.
address@hidden M-x eval-buffer
+Evaluate all the Lisp expressions in the buffer.
address@hidden table
+
address@hidden
address@hidden This uses ``colon'' instead of a literal `:' because Info cannot
address@hidden cope with a `:' in a menu
address@hidden address@hidden
address@hidden ifinfo
address@hidden
address@hidden M-:
address@hidden ifnotinfo
address@hidden eval-expression
+ @kbd{M-:} (@code{eval-expression}) is the most basic command for evaluating
+a Lisp expression interactively. It reads the expression using the
+minibuffer, so you can execute any expression on a buffer regardless of
+what the buffer contains. When the expression is evaluated, the current
+buffer is once again the buffer that was current when @kbd{M-:} was
+typed.
+
address@hidden C-M-x @r{(Emacs-Lisp mode)}
address@hidden eval-defun
+ In Emacs-Lisp mode, the key @kbd{C-M-x} is bound to the command
address@hidden, which parses the defun containing or following point
+as a Lisp expression and evaluates it. The value is printed in the echo
+area. This command is convenient for installing in the Lisp environment
+changes that you have just made in the text of a function definition.
+
+ @kbd{C-M-x} treats @code{defvar} expressions specially. Normally,
+evaluating a @code{defvar} expression does nothing if the variable it
+defines already has a value. But @kbd{C-M-x} unconditionally resets the
+variable to the initial value specified in the @code{defvar} expression.
address@hidden expressions are treated similarly.
+This special feature is convenient for debugging Lisp programs.
+Typing @kbd{C-M-x} on a @code{defface} expression reinitializes
+the face according to the @code{defface} specification.
+
address@hidden C-x C-e
address@hidden eval-last-sexp
+ The command @kbd{C-x C-e} (@code{eval-last-sexp}) evaluates the Lisp
+expression preceding point in the buffer, and displays the value in the
+echo area. It is available in all major modes, not just Emacs-Lisp
+mode. It does not treat @code{defvar} specially.
+
+ When the result of an evaluation is an integer, you can type
address@hidden C-e} a second time to display the value of the integer result
+in additional formats (octal, hexadecimal, and character).
+
+ If @kbd{C-x C-e}, or @kbd{M-:} is given a numeric argument, it
+inserts the value into the current buffer at point, rather than
+displaying it in the echo area. The argument's value does not matter.
address@hidden with a numeric argument instruments the function
+definition for Edebug (@pxref{Instrumenting, Instrumenting for Edebug,, elisp,
the Emacs Lisp Reference Manual}).
+
address@hidden eval-region
address@hidden eval-buffer
+ The most general command for evaluating Lisp expressions from a buffer
+is @code{eval-region}. @kbd{M-x eval-region} parses the text of the
+region as one or more Lisp expressions, evaluating them one by one.
address@hidden eval-buffer} is similar but evaluates the entire
+buffer. This is a reasonable way to install the contents of a file of
+Lisp code that you are ready to test. Later, as you find bugs and
+change individual functions, use @kbd{C-M-x} on each function that you
+change. This keeps the Lisp world in step with the source file.
+
address@hidden eval-expression-print-level
address@hidden eval-expression-print-length
address@hidden eval-expression-debug-on-error
+ The two customizable variables @code{eval-expression-print-level} and
address@hidden control the maximum depth and length
+of lists to print in the result of the evaluation commands before
+abbreviating them. @code{eval-expression-debug-on-error} controls
+whether evaluation errors invoke the debugger when these commands are
+used; its default is @code{t}.
+
address@hidden Lisp Interaction
address@hidden Lisp Interaction Buffers
+
+ The buffer @samp{*scratch*} which is selected when Emacs starts up is
+provided for evaluating Lisp expressions interactively inside Emacs.
+
+ The simplest way to use the @samp{*scratch*} buffer is to insert Lisp
+expressions and type @kbd{C-j} after each expression. This command
+reads the Lisp expression before point, evaluates it, and inserts the
+value in printed representation before point. The result is a complete
+typescript of the expressions you have evaluated and their values.
+
+ The @samp{*scratch*} buffer's major mode is Lisp Interaction mode, which
+is the same as Emacs-Lisp mode except for the binding of @kbd{C-j}.
+
address@hidden lisp-interaction-mode
+ The rationale for this feature is that Emacs must have a buffer when
+it starts up, but that buffer is not useful for editing files since a
+new buffer is made for every file that you visit. The Lisp interpreter
+typescript is the most useful thing I can think of for the initial
+buffer to do. Type @kbd{M-x lisp-interaction-mode} to put the current
+buffer in Lisp Interaction mode.
+
address@hidden ielm
+ An alternative way of evaluating Emacs Lisp expressions interactively
+is to use Inferior Emacs-Lisp mode, which provides an interface rather
+like Shell mode (@pxref{Shell Mode}) for evaluating Emacs Lisp
+expressions. Type @kbd{M-x ielm} to create an @samp{*ielm*} buffer
+which uses this mode. For more information see that command's
+documentation.
+
address@hidden External Lisp
address@hidden Running an External Lisp
+
+ Emacs has facilities for running programs in other Lisp systems. You can
+run a Lisp process as an inferior of Emacs, and pass expressions to it to
+be evaluated. You can also pass changed function definitions directly from
+the Emacs buffers in which you edit the Lisp programs to the inferior Lisp
+process.
+
address@hidden run-lisp
address@hidden inferior-lisp-program
address@hidden C-x C-z
+ To run an inferior Lisp process, type @kbd{M-x run-lisp}. This runs
+the program named @code{lisp}, the same program you would run by typing
address@hidden as a shell command, with both input and output going through
+an Emacs buffer named @samp{*lisp*}. That is to say, any ``terminal
+output'' from Lisp will go into the buffer, advancing point, and any
+``terminal input'' for Lisp comes from text in the buffer. (You can
+change the name of the Lisp executable file by setting the variable
address@hidden)
+
+ To give input to Lisp, go to the end of the buffer and type the input,
+terminated by @key{RET}. The @samp{*lisp*} buffer is in Inferior Lisp
+mode, which combines the special characteristics of Lisp mode with most
+of the features of Shell mode (@pxref{Shell Mode}). The definition of
address@hidden to send a line to a subprocess is one of the features of Shell
+mode.
+
address@hidden lisp-mode
+ For the source files of programs to run in external Lisps, use Lisp
+mode. You can switch to this mode with @kbd{M-x lisp-mode}, and it is
+used automatically for files whose names end in @file{.l},
address@hidden, or @file{.lisp}.
+
address@hidden C-M-x @r{(Lisp mode)}
address@hidden lisp-eval-defun
+ When you edit a function in a Lisp program you are running, the easiest
+way to send the changed definition to the inferior Lisp process is the key
address@hidden In Lisp mode, this runs the function @code{lisp-eval-defun},
+which finds the defun around or following point and sends it as input to
+the Lisp process. (Emacs can send input to any inferior process regardless
+of what buffer is current.)
+
+ Contrast the meanings of @kbd{C-M-x} in Lisp mode (for editing
+programs to be run in another Lisp system) and Emacs-Lisp mode (for
+editing Lisp programs to be run in Emacs; see @pxref{Lisp Eval}): in
+both modes it has the effect of installing the function definition
+that point is in, but the way of doing so is different according to
+where the relevant Lisp environment is found.
+
+
address@hidden
+ arch-tag: 9c3c2f71-b332-4144-8500-3ff9945a50ed
address@hidden ignore