1# serial 20 2 3# See if we need to emulate a missing ftruncate function using chsize. 4 5# Copyright (C) 2000-2001, 2003-2007, 2009-2020 Free Software Foundation, Inc. 6# This file is free software; the Free Software Foundation 7# gives unlimited permission to copy and/or distribute it, 8# with or without modifications, as long as this notice is preserved. 9 10AC_DEFUN([gl_FUNC_FTRUNCATE], 11[ 12 AC_REQUIRE([gl_UNISTD_H_DEFAULTS]) 13 AC_CHECK_FUNCS_ONCE([ftruncate]) 14 if test $ac_cv_func_ftruncate = yes; then 15 m4_ifdef([gl_LARGEFILE], [ 16 AC_REQUIRE([AC_CANONICAL_HOST]) 17 case "$host_os" in 18 mingw*) 19 dnl Native Windows, and Large File Support is requested. 20 dnl The MSVCRT _chsize() function only accepts a 32-bit file size, 21 dnl and the mingw64 ftruncate64() function is unreliable (it may 22 dnl delete the file, see 23 dnl <https://web.archive.org/web/20160425005423/http://mingw-w64.sourcearchive.com/documentation/2.0-1/ftruncate64_8c_source.html>). 24 dnl Use gnulib's ftruncate() implementation instead. 25 REPLACE_FTRUNCATE=1 26 ;; 27 esac 28 ], [ 29 : 30 ]) 31 else 32 HAVE_FTRUNCATE=0 33 fi 34]) 35 36# Prerequisites of lib/ftruncate.c. 37AC_DEFUN([gl_PREREQ_FTRUNCATE], 38[ 39 AC_CHECK_FUNCS([chsize]) 40]) 41