Handle varalias chains, custom variables in #'user-variable-p. src/ChangeLog addition: 2008-08-23 Aidan Kehoe <kehoea@parhasard.net> * eval.c (Fuser_variable_p): Moved to symbols.c * symbols.c (Fcustom_variable_p): Moved here from custom.el. (user_variable_alias_check_fun): Mapper function used in `user-variable-p'. (Fuser_variable_p): Moved here from eval.c, to allow it to examine the variable alias chain. Expanded to check each entry in the variable alias chain for signs of being a user variable; documentation updated, noting the differences between GNU's behaviour and ours (ours is a little more sensible) (map_varalias_chain): New. Given a C function, call it at least once for each symbol in a symbol's varalias chain, signalling an error if there's a cycle, and returning immediately if the function returns something other than Qzero. (Fdefvaralias): Correct the use of the word "alias" in the docstring and in the argument name. Motivate this in a comment. Add support for a DOCSTRING argument, something GNU has too, and document this * gc.c (vars_of_gc): Start the docstring of `garbage-collection-messages' with an asterisk, to indicate that it's a user variable. lisp/ChangeLog addition: 2008-08-23 Aidan Kehoe <kehoea@parhasard.net> * custom.el: Move #'custom-variable-p to C, since it's now called from #'user-variable-p.

/* Program to produce output at regular intervals.  */

#include <config.h>

#if __STDC__ || defined(STDC_HEADERS)
#include <stdlib.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#endif

#include <stdio.h>
#include <sys/types.h>

#ifdef WIN32_NATIVE
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#undef sleep
#define sleep(t) Sleep ((t) * 1000)
#define getppid() (0)
#undef HAVE_SYS_TIME_H
#endif /* WIN32_NATIVE */

#ifdef TIME_WITH_SYS_TIME
#include <sys/time.h>
#include <time.h>
#else
#ifdef HAVE_SYS_TIME_H
#include <sys/time.h>
#else
#include <time.h>
#endif
#endif

int
main (int argc, char *argv[])
{
  int period = 60;

  if (argc > 1)
    period = atoi (argv[1]);

  while (1)
    {
      /* Make sure wakeup stops when Emacs goes away.  */
      if (getppid () == 1)
	return 0;
      printf ("Wake up!\n");
      /* If fflush fails, then our stdout pipe is broken. */
      if (fflush (stdout) != 0)
	return 0;
      /* If using a period of 60, produce the output when the minute
	 changes. */
      if (period == 60)
	{
	  time_t when;
	  struct tm *tp;
	  time (&when);
	  tp = localtime (&when);
	  sleep (60 - tp->tm_sec);
	}
      else
	sleep (period);
    }
}