Tolerate declared but missing pipe2 syscall.

diff --git a/ChangeLog b/ChangeLog
index 438cc9c..3f8349d 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,16 @@
 2009-08-23  Bruno Haible  <bruno@clisp.org>
 
+       Tolerate declared but missing pipe2 syscall.
+       * lib/pipe2.c (pipe2): Invoke original pipe2 function first, if
+       available.
+       * lib/unistd.in.h (pipe2): If the function is already present,
+       override it.
+       * m4/pipe2.m4 (gl_FUNC_PIPE2): Remove AC_LIBOBJ invocation.
+       * modules/pipe2 (Makefile.am): Compile pipe2.c always.
+       Reported by Paolo Bonzini.
+
+2009-08-23  Bruno Haible  <bruno@clisp.org>
+
        * lib/pipe2.c (pipe2): Move #ifs inside function.
 
 2009-08-22  Joel E. Denny  <jdenny@clemson.edu>

diff --git a/lib/pipe2.c b/lib/pipe2.c
index d5833dd..c18860d 100644 (file)
--- a/lib/pipe2.c
+++ b/lib/pipe2.c
@@ -40,6 +40,17 @@
 int
 pipe2 (int fd[2], int flags)
 {
+#if HAVE_PIPE2
+# undef pipe2
+  /* Try the system call first, if it exists.  (We may be running with a glibc
+     that has the function but with an older kernel that lacks it.)  */
+  {
+    int result = pipe2 (fd, flags);
+    if (!(result < 0 && errno == ENOSYS))
+      return result;
+  }
+#endif
+
 #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
 /* Native Woe32 API.  */
 

diff --git a/lib/unistd.in.h b/lib/unistd.in.h
index 7dd9834..2f3be17 100644 (file)
--- a/lib/unistd.in.h
+++ b/lib/unistd.in.h
@@ -562,9 +562,10 @@ extern int link (const char *path1, const char *path2);
    Return 0 upon success, or -1 with errno set upon failure.
    See also the Linux man page at
    <http://www.kernel.org/doc/man-pages/online/pages/man2/pipe2.2.html>.  */
-# if !@HAVE_PIPE2@
-extern int pipe2 (int fd[2], int flags);
+# if @HAVE_PIPE2@
+#  define pipe2 rpl_pipe2
 # endif
+extern int pipe2 (int fd[2], int flags);
 #elif defined GNULIB_POSIXCHECK
 # undef pipe2
 # define pipe2(f,o) \

diff --git a/m4/pipe2.m4 b/m4/pipe2.m4
index d0aae43..54f6ec7 100644 (file)
--- a/m4/pipe2.m4
+++ b/m4/pipe2.m4
@@ -1,4 +1,4 @@
-# pipe2.m4 serial 1
+# pipe2.m4 serial 2
 dnl Copyright (C) 2009 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -14,6 +14,5 @@ AC_DEFUN([gl_FUNC_PIPE2],
   AC_CHECK_FUNCS_ONCE([pipe2])
   if test $ac_cv_func_pipe2 != yes; then
     HAVE_PIPE2=0
-    AC_LIBOBJ([pipe2])
   fi
 ])

diff --git a/modules/pipe2 b/modules/pipe2
index 9117e73..036d873 100644 (file)
--- a/modules/pipe2
+++ b/modules/pipe2
@@ -15,6 +15,7 @@ gl_FUNC_PIPE2
 gl_UNISTD_MODULE_INDICATOR([pipe2])
 
 Makefile.am:
+lib_SOURCES += pipe2.c
 
 Include:
 <unistd.h>