BSD signal blocking

[Bruno Haible <haible at ilog dot fr>]

Programs that make use of BSD signal blocking functions, like the following
one, cannot be compiled with CC="gcc -ansi" on Linux, because the libc is
missing the sigmask() function. Therefore sigmask() should be added to the
libc.

Sample program:

#include <signal.h>
int main()
{
  int wasblocked = ((sigblock(0) & sigmask(SIGALRM)) != 0);
  exit(wasblocked);
}

It produces:

$ gcc foo.c
$ gcc -ansi foo.c
/tmp/cclSazAu.o: In function `main':
/tmp/cclSazAu.o(.text+0x1c): undefined reference to `sigmask'
collect2: ld returned 1 exit status

Here is a fix.


2000-07-08  Bruno Haible  <haible@clisp.cons.org>

	* sysdeps/generic/sigmask.c: New file.
	* signal/Makefile (routines): Add sigmask.
	* signal/Versions: Add sigmask.

*** sysdeps/generic/sigmask.c.bak	Sat Jul  8 22:32:30 2000
--- sysdeps/generic/sigmask.c	Sat Jul  8 22:38:35 2000
***************
*** 0 ****
--- 1,28 ----
+ /* Copyright (C) 2000 Free Software Foundation, Inc.
+    This file is part of the GNU C Library.
+ 
+    The GNU C Library is free software; you can redistribute it and/or
+    modify it under the terms of the GNU Library General Public License as
+    published by the Free Software Foundation; either version 2 of the
+    License, or (at your option) any later version.
+ 
+    The GNU C Library is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+    Library General Public License for more details.
+ 
+    You should have received a copy of the GNU Library General Public
+    License along with the GNU C Library; see the file COPYING.LIB.  If not,
+    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+    Boston, MA 02111-1307, USA.  */
+ 
+ #include <signal.h>
+ 
+ #undef sigmask
+ 
+ /* Compute mask for signal SIG.  */
+ int
+ sigmask (int sig)
+ {
+   return __sigmask (sig);
+ }
*** signal/Makefile.bak	Tue Sep  7 17:06:02 1999
--- signal/Makefile	Sat Jul  8 22:35:52 2000
***************
*** 28,34 ****
  routines	:= signal raise killpg \
  		   sigaction sigprocmask kill \
  		   sigpending sigsuspend sigwait \
! 		   sigblock sigsetmask sigpause sigvec \
  		   sigstack sigaltstack sigintr \
  		   sigsetops sigempty sigfillset sigaddset sigdelset sigismem \
  		   sigreturn \
--- 28,34 ----
  routines	:= signal raise killpg \
  		   sigaction sigprocmask kill \
  		   sigpending sigsuspend sigwait \
! 		   sigmask sigblock sigsetmask sigpause sigvec \
  		   sigstack sigaltstack sigintr \
  		   sigsetops sigempty sigfillset sigaddset sigdelset sigismem \
  		   sigreturn \
*** signal/Versions.bak	Mon Feb 28 11:38:00 2000
--- signal/Versions	Sat Jul  8 22:37:45 2000
***************
*** 48,52 ****
--- 48,55 ----
    GLIBC_2.2 {
      # Needed to provide a pointer to the XPG sigpause function.
      __xpg_sigpause;
+ 
+     # s*
+     sigmask;
    }
  }