round: Update regarding AIX.

[gnulib.git] / m4 / lseek.m4

diff --git a/m4/lseek.m4 b/m4/lseek.m4
index 075c2f4..9bf4dc2 100644 (file)
--- a/m4/lseek.m4
+++ b/m4/lseek.m4
@@ -1,5 +1,5 @@
-# lseek.m4 serial 1
-dnl Copyright (C) 2007 Free Software Foundation, Inc.
+# lseek.m4 serial 5
+dnl Copyright (C) 2007, 2009, 2010 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -9,12 +9,33 @@ AC_DEFUN([gl_FUNC_LSEEK],
   AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
   AC_REQUIRE([AC_PROG_CC])
   AC_CACHE_CHECK([whether lseek detects pipes], [gl_cv_func_lseek_pipe],
-    [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([#include <unistd.h>],
-[#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
-/* mingw mistakenly returns 0 when trying to seek on pipes.  */
+    [if test $cross_compiling = no; then
+       AC_LINK_IFELSE([
+#include <sys/types.h> /* for off_t */
+#include <stdio.h> /* for SEEK_CUR */
+#include <unistd.h>
+int main ()
+{
+  /* Exit with success only if stdin is seekable.  */
+  return lseek (0, (off_t)0, SEEK_CUR) < 0;
+}],
+         [if test -s conftest$ac_exeext \
+             && ./conftest$ac_exeext < conftest.$ac_ext \
+             && test 1 = "`echo hi \
+               | { ./conftest$ac_exeext; echo $?; cat >/dev/null; }`"; then
+            gl_cv_func_lseek_pipe=yes
+          else
+            gl_cv_func_lseek_pipe=no
+          fi],
+         [gl_cv_func_lseek_pipe=no])
+     else
+       AC_COMPILE_IFELSE([
+#if ((defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__) || defined __BEOS__
+/* mingw and BeOS mistakenly return 0 when trying to seek on pipes.  */
   Choke me.
-#endif])],
-      [gl_cv_func_lseek_pipe=yes], [gl_cv_func_lseek_pipe=no])])
+#endif],
+         [gl_cv_func_lseek_pipe=yes], [gl_cv_func_lseek_pipe=no])
+     fi])
   if test $gl_cv_func_lseek_pipe = no; then
     gl_REPLACE_LSEEK
   fi
@@ -26,5 +47,5 @@ AC_DEFUN([gl_REPLACE_LSEEK],
   AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
   REPLACE_LSEEK=1
   AC_DEFINE([LSEEK_PIPE_BROKEN], [1],
-           [Define to 1 if lseek does not detect pipes.])
+            [Define to 1 if lseek does not detect pipes.])
 ])