Date: Sun, 1 Feb 1998 20:48:01 +0200 (IST)
From: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
To: DJ Delorie <dj AT delorie DOT com>
cc: djgpp-workers AT delorie DOT com
Subject: Re: NSIG ?
In-Reply-To: <199801111912.OAA25455@delorie.com>
Message-ID: <Pine.SUN.3.91.980201204437.16669A-100000@is>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
Precedence: bulk


On Sun, 11 Jan 1998, DJ Delorie wrote:

> > Should we add NSIG in v2.02?
> 
> Only if we're prepared to add _sys_siglist[] also.

Here it is (together with a compatibility function `psignal' as desert).

If you wonder why did I go to such lengths instead of just defining a
static array, then that's because the static solution resulted in a 7KB
object file, most of which is the same string again and again, whereas
this one is only 2KB. 

*** /dev/null	Sat Jan 31 19:59:48 1998
--- src/libc/compat/signal/siglist.c	Sat Jan 31 19:19:16 1998
***************
*** 0 ****
--- 1,96 ----
+ /* Copyright (C) 1997 DJ Delorie, see COPYING.DJ for details */
+ 
+ #include <signal.h>
+ #include <string.h>
+ #include <stdlib.h>
+ 
+ char *sys_siglist[NSIG + 1]; /* initially all-zero */
+ 
+ static const char *known_signal[] = {
+   "Abort termination",
+   "Floating-point exception",
+   "Illegal instruction",
+   "Segmentation violation",
+   "Software termination signal",
+   "Alarm clock",
+   "Hangup",
+   "Interrupt",
+   "Kill",
+   "Write on pipe with no one to read it",
+   "Quit",
+   "User-defined signal 1",
+   "User-defined signal 2",
+   "Floating-point co-processor not present",
+   "Debugger/Breakpoint instruction",
+   "Timer tick signal",
+   "Profiler signal"
+ };
+ 
+ static char unknown_signal[]  = "Unknown signal";
+ 
+ static void
+ put_hex_digits (char *str, int num, size_t idx)
+ {
+   static char xdigits[] = "0123456789ABCDEF";
+ 
+   str[idx] = xdigits[num / 16];
+   str[idx + 1] = xdigits[num & 15];
+ }
+ 
+ static char *
+ xstrdup (const char *src)
+ {
+   if (src)
+   {
+     size_t src_size = strlen (src) + 1;
+     char *new = (char *)malloc (src_size);
+ 
+     if (new)
+     {
+       memcpy (new, src, src_size);
+       return new;
+     }
+   }
+ 
+   return NULL;
+ }
+ 
+ static int signum;
+ 
+ static void
+ fill_dull_names (const char *template, size_t tpl_size, int count)
+ {
+   int i;
+ 
+   for (i = 0; i < count; i++)
+   {
+     char *signame = (char *)malloc (tpl_size);
+ 
+     memcpy (signame, template, tpl_size);
+     put_hex_digits (signame, i, tpl_size - 3);
+     sys_siglist[signum++] = signame;
+   }
+ }
+ 
+ static void __attribute__((constructor))
+ init_sys_siglist (void)
+ {
+   static char int_name[]   = "Interrupt XXh";
+   static size_t int_size   = sizeof(int_name);
+   static char excpt_name[] = "Exception XXh";
+   static size_t excpt_size = sizeof(excpt_name);
+   int i;
+ 
+   signum = 0;
+ 
+   fill_dull_names (int_name, int_size, 256);
+   fill_dull_names (excpt_name, excpt_size, 32);
+ 
+   for (i = 0; i < 17; i++)
+     sys_siglist[signum++] = xstrdup (known_signal[i]);
+ 
+   for (i = 305; i < 320; i++)
+     sys_siglist[signum++] = xstrdup (unknown_signal);
+ 
+   sys_siglist[signum] = 0;
+ }
*** /dev/null	Sat Jan 31 20:00:15 1998
--- src/libc/compat/signal/psignal.c	Sat Jan 31 19:40:54 1998
***************
*** 0 ****
--- 1,13 ----
+ /* Copyright (C) 1997 DJ Delorie, see COPYING.DJ for details */
+ 
+ #include <signal.h>
+ #include <stdio.h>
+ 
+ void
+ psignal (int sig, const char *msg)
+ {
+   if (sig >= 0 && sig < NSIG)
+     fprintf (stderr, "%s: %s\n", msg, sys_siglist[sig]);
+   else
+     fprintf (stderr, "%s: signal %d\n", msg, sig);
+ }
*** /dev/null	Sat Jan 31 20:00:26 1998
--- src/libc/compat/signal/siglist.txh	Sat Jan 31 19:54:50 1998
***************
*** 0 ****
--- 1,33 ----
+ @c ----------------------------------------------------------------------
+ 
+ @node psignal, signal
+ @subheading Syntax
+ 
+ @example
+ #include <signal.h>
+ 
+ extern char *sys_siglist[];
+ void psignal (int sig, const char *msg);
+ @end example
+ 
+ @subheading Description
+ 
+ This function produces a message on the standard error stream describing
+ the signal given by its number in @var{sig}.  It prints the string
+ pointed to by @var{msg}, then the name of the signal, and a newline.
+ 
+ The names of signals can be retrieved using the array
+ @code{sys_siglist}, with the signal number serving as an index into this
+ array.
+ 
+ @subheading Example
+ 
+ @example
+   #include <signal.h>
+ 
+   void sig_catcher (int sig)
+   @{
+     psignal (progname, sig);
+     return;
+   @}
+ @end example
*** /dev/null	Sat Jan 31 20:00:54 1998
--- src/libc/compat/signal/makefile	Sat Jan 31 19:56:56 1998
***************
*** 0 ****
--- 1,7 ----
+ # Copyright (C) 1997 DJ Delorie, see COPYING.DJ for details
+ TOP=../..
+ 
+ SRC += siglist.c
+ SRC += psignal.c
+ 
+ include $(TOP)/../makefile.inc
*** include/signal.h~0	Sat Apr 27 00:14:42 1996
--- include/signal.h	Sat Jan 31 19:54:58 1998
***************
*** 78,83 ****
--- 78,89 ----
  #define SIGPROF 304
  #define SIGMAX 320
  
+ #define NSIG SIGMAX
+ 
+ extern char *sys_siglist[];
+ 
+ void	psignal(int _sig, const char *_msg);
+ 
  #endif /* !_POSIX_SOURCE */
  #endif /* !__STRICT_ANSI__ */
  #endif /* !__dj_ENFORCE_ANSI_FREESTANDING */