X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Fftruncate.m4;h=29c76ccfca0997260513643f1cda47733aad4065;hb=1276a2c5f24c0c932426aca9c899fa524d2443f2;hp=c225e48a3ed4e452cfcb7b4e09b9cdf76f81a3cb;hpb=7c3f8da8f075e3813ced160d5b53a28c6f7dfe78;p=gnulib.git

diff --git a/m4/ftruncate.m4 b/m4/ftruncate.m4
index c225e48a3..29c76ccfc 100644
--- a/m4/ftruncate.m4
+++ b/m4/ftruncate.m4
@@ -1,22 +1,40 @@
-#serial 8
+# serial 20
 
-# See if we need to emulate a missing ftruncate function using fcntl or chsize.
+# See if we need to emulate a missing ftruncate function using chsize.
 
-# Copyright (C) 2000, 2001, 2003, 2004, 2005 Free Software Foundation, Inc.
+# Copyright (C) 2000-2001, 2003-2007, 2009-2014 Free Software Foundation, Inc.
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
 # with or without modifications, as long as this notice is preserved.
 
 AC_DEFUN([gl_FUNC_FTRUNCATE],
 [
-  AC_REPLACE_FUNCS(ftruncate)
-  if test $ac_cv_func_ftruncate = no; then
-    gl_PREREQ_FTRUNCATE
+  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+  AC_CHECK_FUNCS_ONCE([ftruncate])
+  if test $ac_cv_func_ftruncate = yes; then
+    m4_ifdef([gl_LARGEFILE], [
+      AC_REQUIRE([AC_CANONICAL_HOST])
+      case "$host_os" in
+        mingw*)
+          dnl Native Windows, and Large File Support is requested.
+          dnl The MSVCRT _chsize() function only accepts a 32-bit file size,
+          dnl and the mingw64 ftruncate64() function is unreliable (it may
+          dnl delete the file, see
+          dnl <http://mingw-w64.sourcearchive.com/documentation/2.0-1/ftruncate64_8c_source.html>).
+          dnl Use gnulib's ftruncate() implementation instead.
+          REPLACE_FTRUNCATE=1
+          ;;
+      esac
+    ], [
+      :
+    ])
+  else
+    HAVE_FTRUNCATE=0
   fi
 ])
 
 # Prerequisites of lib/ftruncate.c.
 AC_DEFUN([gl_PREREQ_FTRUNCATE],
 [
-  AC_CHECK_FUNCS(chsize)
+  AC_CHECK_FUNCS([chsize])
 ])