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[gnulib.git] / lib / pipe2.c

diff --git a/lib/pipe2.c b/lib/pipe2.c
index d5833dd..2d973dc 100644 (file)
--- a/lib/pipe2.c
+++ b/lib/pipe2.c
@@ -1,5 +1,5 @@
 /* Create a pipe, with specific opening flags.
-   Copyright (C) 2009 Free Software Foundation, Inc.
+   Copyright (C) 2009, 2010 Free Software Foundation, Inc.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -23,6 +23,8 @@
 #include <errno.h>
 #include <fcntl.h>
 
+#include "binary-io.h"
+
 #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
 /* Native Woe32 API.  */
 
@@ -40,6 +42,26 @@
 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.)  */
+  {
+    /* Cache the information whether the system call really exists.  */
+    static int have_pipe2_really; /* 0 = unknown, 1 = yes, -1 = no */
+    if (have_pipe2_really >= 0)
+      {
+        int result = pipe2 (fd, flags);
+        if (!(result < 0 && errno == ENOSYS))
+          {
+            have_pipe2_really = 1;
+            return result;
+          }
+        have_pipe2_really = -1;
+      }
+  }
+#endif
+
 #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
 /* Native Woe32 API.  */
 
@@ -74,10 +96,10 @@ pipe2 (int fd[2], int flags)
       int fcntl_flags;
 
       if ((fcntl_flags = fcntl (fd[1], F_GETFL, 0)) < 0
-         || fcntl (fd[1], F_SETFL, fcntl_flags | O_NONBLOCK) == -1
-         || (fcntl_flags = fcntl (fd[0], F_GETFL, 0)) < 0
-         || fcntl (fd[0], F_SETFL, fcntl_flags | O_NONBLOCK) == -1)
-       goto fail;
+          || fcntl (fd[1], F_SETFL, fcntl_flags | O_NONBLOCK) == -1
+          || (fcntl_flags = fcntl (fd[0], F_GETFL, 0)) < 0
+          || fcntl (fd[0], F_SETFL, fcntl_flags | O_NONBLOCK) == -1)
+        goto fail;
     }
 
   if (flags & O_CLOEXEC)
@@ -85,10 +107,10 @@ pipe2 (int fd[2], int flags)
       int fcntl_flags;
 
       if ((fcntl_flags = fcntl (fd[1], F_GETFD, 0)) < 0
-         || fcntl (fd[1], F_SETFD, fcntl_flags | FD_CLOEXEC) == -1
-         || (fcntl_flags = fcntl (fd[0], F_GETFD, 0)) < 0
-         || fcntl (fd[0], F_SETFD, fcntl_flags | FD_CLOEXEC) == -1)
-       goto fail;
+          || fcntl (fd[1], F_SETFD, fcntl_flags | FD_CLOEXEC) == -1
+          || (fcntl_flags = fcntl (fd[0], F_GETFD, 0)) < 0
+          || fcntl (fd[0], F_SETFD, fcntl_flags | FD_CLOEXEC) == -1)
+        goto fail;
     }
 
 # if O_BINARY