+ /* Mingw _pipe() corrupts fd on failure; also, if we succeed at
+ creating the pipe but later fail at changing fcntl, we want
+ to leave fd unchanged: http://austingroupbugs.net/view.php?id=467 */
+ int tmp[2];
+ tmp[0] = fd[0];
+ tmp[1] = fd[1];
+
+#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