Fix lseek on mingw.

[gnulib.git] / m4 / lseek.m4

diff --git a/m4/lseek.m4 b/m4/lseek.m4
new file mode 100644 (file)
index 0000000..075c2f4
--- /dev/null
+++ b/m4/lseek.m4
@@ -0,0 +1,30 @@
+# lseek.m4 serial 1
+dnl Copyright (C) 2007 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.
+
+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.  */
+  Choke me.
+#endif])],
+      [gl_cv_func_lseek_pipe=yes], [gl_cv_func_lseek_pipe=no])])
+  if test $gl_cv_func_lseek_pipe = no; then
+    gl_REPLACE_LSEEK
+  fi
+])
+
+AC_DEFUN([gl_REPLACE_LSEEK],
+[
+  AC_LIBOBJ([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.])
+])