proposed getitimer and setitimer functions

[Rob Browning]

Is the following implementation of/interface for setitimer OK?  I need
to add real docs, but in summary, you call it like this:

  (setitimer which-timer
             interval-secs interval-microsecs
             value-secs value-microsecs)

and it returns a three element list:

  (result-int
   (old-timer-interval-secs . old-timer-interval-microsecs)
   (old-timer-value-secs . old-timer-value-microsecs))

Also, what about the getitimer code below?  You call it like this:

  (getitimer which-timer)

and it returns a result structured the same as with setitimer.

Finally, this patch defines ITIMER_REAL, ITIMER_VIRTUAL, and
ITIMER_PROF.

If all of this is OK (and not to big a change), I'd like to commit it
now for 1.6.0 which I'll be branching before Sun.  These two functions
are needed by anyone trying to build a statistical profiler.

(Oh, and is there any rule of thumb about when you're supposed to use
 SCM_VALIDATE_FOO vs just letting scm_foo2bar handle signaling an
 error?)

Thanks

Index: libguile/scmsigs.c
===================================================================
RCS file: /cvsroot/guile/guile/guile-core/libguile/scmsigs.c,v
retrieving revision 1.60
diff -u -r1.60 scmsigs.c
--- libguile/scmsigs.c  2001/06/26 17:53:09     1.60
+++ libguile/scmsigs.c  2001/07/06 17:44:45
@@ -46,6 +46,7 @@
 
 #include <signal.h>
 #include <errno.h>
+#include <stdio.h>
 
 #include "libguile/_scm.h"
 
@@ -417,6 +418,64 @@
 }
 #undef FUNC_NAME
 
+SCM_DEFINE (scm_setitimer, "setitimer", 5, 0, 0,
+           (SCM which_timer,
+            SCM interval_seconds, SCM interval_microseconds,
+            SCM value_seconds, SCM value_microseconds),
+           "Undocumented yet.")
+#define FUNC_NAME s_scm_setitimer
+{
+  int result;
+  int c_which_timer;
+  struct itimerval new_timer;
+  struct itimerval old_timer;
+
+  SCM_VALIDATE_INUM (1, which_timer);
+  SCM_VALIDATE_NUMBER (2, interval_seconds);
+  SCM_VALIDATE_NUMBER (3, interval_microseconds);
+  SCM_VALIDATE_NUMBER (4, value_seconds);
+  SCM_VALIDATE_NUMBER (5, value_microseconds);
+
+  c_which_timer = SCM_INUM(which_timer);
+
+  new_timer.it_interval.tv_sec = scm_num2long(interval_seconds, 0, NULL);
+  new_timer.it_interval.tv_usec = scm_num2long(interval_microseconds, 0, NULL);
+  new_timer.it_value.tv_sec = scm_num2long(value_seconds, 0, NULL);
+  new_timer.it_value.tv_usec = scm_num2long(value_microseconds, 0, NULL);
+
+  result = setitimer(c_which_timer, &new_timer, &old_timer);
+  
+  return scm_list_3(SCM_MAKINUM(result),
+                    scm_cons(scm_long2num(old_timer.it_interval.tv_sec),
+                             scm_long2num(old_timer.it_interval.tv_usec)),
+                    scm_cons(scm_long2num(old_timer.it_value.tv_sec),
+                             scm_long2num(old_timer.it_value.tv_usec)));
+}
+#undef FUNC_NAME
+
+SCM_DEFINE (scm_getitimer, "getitimer", 1, 0, 0,
+           (SCM which_timer),
+           "Undocumented yet.")
+#define FUNC_NAME s_scm_getitimer
+{
+  int result;
+  int c_which_timer;
+  struct itimerval old_timer;
+
+  SCM_VALIDATE_INUM (1, which_timer);
+
+  c_which_timer = SCM_INUM(which_timer);
+
+  result = getitimer(c_which_timer, &old_timer);
+  
+  return scm_list_3(SCM_MAKINUM(result),
+                    scm_cons(scm_long2num(old_timer.it_interval.tv_sec),
+                             scm_long2num(old_timer.it_interval.tv_usec)),
+                    scm_cons(scm_long2num(old_timer.it_value.tv_sec),
+                             scm_long2num(old_timer.it_value.tv_usec)));
+}
+#undef FUNC_NAME
+
 #ifdef HAVE_PAUSE
 SCM_DEFINE (scm_pause, "pause", 0, 0, 0,
            (),
@@ -553,6 +612,11 @@
 #ifdef SA_RESTART
   scm_c_define ("SA_RESTART", scm_long2num (SA_RESTART));
 #endif
+
+  /* Stuff needed by setitimer. */
+  scm_c_define ("ITIMER_REAL", SCM_MAKINUM (ITIMER_REAL));
+  scm_c_define ("ITIMER_VIRTUAL", SCM_MAKINUM (ITIMER_VIRTUAL));
+  scm_c_define ("ITIMER_PROF", SCM_MAKINUM (ITIMER_PROF));
 
 #ifndef SCM_MAGIC_SNARFER
 #include "libguile/scmsigs.x"


-- 
Rob Browning
rlb @defaultvalue.org, @linuxdevel.com, and @debian.org
Previously @cs.utexas.edu
GPG=1C58 8B2C FB5E 3F64 EA5C  64AE 78FE E5FE F0CB A0AD