Support signal handling with SIGPIPE on native Windows platforms.

ChangeLog

@@ -23,6 +23,16 @@
 
 2008-09-26  Bruno Haible  <bruno@clisp.org>
 
+	* lib/signal.in.h (SIGPIPE): Define to a replacement value.
+	(raise): New declaration.
+	* lib/sigprocmask.c (SIGPIPE_handler): New variable.
+	(ext_signal): New function.
+	(rpl_raise): New function.
+	* m4/signal_h.m4 (gl_SIGNAL_H_DEFAULTS): Initialize
+	GNULIB_SIGNAL_H_SIGPIPE.
+	* modules/signal (Makefile.am): Substitute GNULIB_SIGNAL_H_SIGPIPE.
+	* doc/posix-headers/signal.texi: Mention the SIGPIPE issue.
+
 	* modules/sigpipe: New file.
 	* m4/sigpipe.m4: New file.
 

doc/posix-headers/signal.texi

@@ -10,18 +10,22 @@ Portability problems fixed by Gnulib:
 @item
 @code{sigset_t} is only declared in <sys/types.h> on some platforms:
 mingw.
-
 @item
 @code{struct sigaction} and @code{siginfo_t} are missing on some
 platforms:
 mingw.
-
 @item
 @code{struct sigaction} lacks the @code{sa_sigaction} member on some
 platforms:
 Irix 5.3, Interix 3.5.
+@item
+The signal @code{SIGPIPE} is not defined on some platforms:
+mingw.
 @end itemize
 
 Portability problems not fixed by Gnulib:
 @itemize
+@item
+Many signals are not defined on some platforms:
+mingw.
 @end itemize

lib/signal.in.h

@@ -44,6 +44,17 @@ extern "C" {
 #endif
 
 
+#if @GNULIB_SIGNAL_H_SIGPIPE@
+# ifndef SIGPIPE
+/* Define SIGPIPE to a value that does not overlap with other signals.  */
+#  define SIGPIPE 13
+#  define GNULIB_defined_SIGPIPE 1
+/* To actually use SIGPIPE, you also need the gnulib modules 'sigprocmask',
+   'write', 'stdio'.  */
+# endif
+#endif
+
+
 #if !@HAVE_POSIX_SIGNALBLOCKING@
 
 /* Maximum signal number + 1.  */
@@ -92,8 +103,18 @@ extern int sigprocmask (int operation, const sigset_t *set, sigset_t *old_set);
    handler.  */
 extern void (*signal (int sig, void (*func) (int))) (int);
 
+# if GNULIB_defined_SIGPIPE
+
+/* Raise signal SIG.  */
+#  undef raise
+#  define raise rpl_raise
+extern int raise (int sig);
+
+# endif
+
 #endif /* !@HAVE_POSIX_SIGNALBLOCKING@ */
 
+
 #if !@HAVE_SIGACTION@
 
 # if !@HAVE_SIGINFO_T@

lib/sigprocmask.c

@@ -45,6 +45,31 @@
 
 typedef void (*handler_t) (int);
 
+/* Handling of gnulib defined signals.  */
+
+#if GNULIB_defined_SIGPIPE
+static handler_t SIGPIPE_handler = SIG_DFL;
+#endif
+
+#if GNULIB_defined_SIGPIPE
+static handler_t
+ext_signal (int sig, handler_t handler)
+{
+  switch (sig)
+    {
+    case SIGPIPE:
+      {
+	handler_t old_handler = SIGPIPE_handler;
+	SIGPIPE_handler = handler;
+	return old_handler;
+      }
+    default: /* System defined signal */
+      return signal (sig, handler);
+    }
+}
+# define signal ext_signal
+#endif
+
 int
 sigismember (const sigset_t *set, int sig)
 {
@@ -240,3 +265,29 @@ rpl_signal (int sig, handler_t handler)
       return SIG_ERR;
     }
 }
+
+#if GNULIB_defined_SIGPIPE
+/* Raise the signal SIG.  */
+int
+rpl_raise (int sig)
+# undef raise
+{
+  switch (sig)
+    {
+    case SIGPIPE:
+      if (blocked_set & (1U << sig))
+	pending_array[sig] = 1;
+      else
+	{
+	  handler_t handler = SIGPIPE_handler;
+	  if (handler == SIG_DFL)
+	    exit (128 + SIGPIPE);
+	  else if (handler != SIG_IGN)
+	    (*handler) (sig);
+	}
+      return 0;
+    default: /* System defined signal */
+      return raise (sig);
+    }
+}
+#endif

m4/signal_h.m4

@@ -1,4 +1,4 @@
-# signal_h.m4 serial 5
+# signal_h.m4 serial 6
 dnl Copyright (C) 2007, 2008 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -19,6 +19,7 @@ AC_DEFUN([gl_SIGNAL_MODULE_INDICATOR],
 
 AC_DEFUN([gl_SIGNAL_H_DEFAULTS],
 [
+  GNULIB_SIGNAL_H_SIGPIPE=0;   AC_SUBST([GNULIB_SIGNAL_H_SIGPIPE])
   GNULIB_SIGPROCMASK=0;        AC_SUBST([GNULIB_SIGPROCMASK])
   GNULIB_SIGACTION=0;          AC_SUBST([GNULIB_SIGACTION])
   dnl Assume proper GNU behavior unless another module says otherwise.

modules/signal

@@ -23,6 +23,7 @@ signal.h: signal.in.h
 	  sed -e 's|@''INCLUDE_NEXT''@|$(INCLUDE_NEXT)|g' \
 	      -e 's|@''PRAGMA_SYSTEM_HEADER''@|@PRAGMA_SYSTEM_HEADER@|g' \
 	      -e 's|@''NEXT_SIGNAL_H''@|$(NEXT_SIGNAL_H)|g' \
+	      -e 's|@''GNULIB_SIGNAL_H_SIGPIPE''@|$(GNULIB_SIGNAL_H_SIGPIPE)|g' \
 	      -e 's|@''GNULIB_SIGPROCMASK''@|$(GNULIB_SIGPROCMASK)|g' \
 	      -e 's|@''GNULIB_SIGACTION''@|$(GNULIB_SIGACTION)|g' \
 	      -e 's|@''HAVE_POSIX_SIGNALBLOCKING''@|$(HAVE_POSIX_SIGNALBLOCKING)|g' \