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# truncate.m4 serial 5 -*- Autoconf -*-
dnl Copyright (C) 2017-2023 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_TRUNCATE],
[
AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
AC_REQUIRE([AC_CANONICAL_HOST])
gl_CHECK_FUNCS_ANDROID([truncate], [[#include <unistd.h>]])
dnl AC_CHECK_FUNC is not enough here, because when compiling for Android 4.4
dnl or older with _FILE_OFFSET_BITS=64, truncate() is not declared. There
dnl is a function 'truncate' in libc, but it is unsuitable, because it takes
dnl only a 32-bit offset argument.
AC_CHECK_DECL([truncate], , , [[#include <unistd.h>]])
if test $ac_cv_have_decl_truncate = yes; then
m4_ifdef([gl_LARGEFILE], [
case "$host_os" in
mingw*)
dnl Native Windows, and Large File Support is requested.
dnl The mingw64 truncate64() function is based on ftruncate64(),
dnl which is unreliable (it may delete the file, see
dnl <https://web.archive.org/web/20160425005423/http://mingw-w64.sourcearchive.com/documentation/2.0-1/ftruncate64_8c_source.html>).
dnl Use gnulib's ftruncate() and truncate() implementation instead.
REPLACE_TRUNCATE=1
;;
esac
], [
:
])
if test $REPLACE_TRUNCATE = 0; then
dnl Check for AIX 7.2 bug with trailing slash.
AC_CACHE_CHECK([whether truncate rejects trailing slashes],
[gl_cv_func_truncate_works],
[echo foo > conftest.tmp
AC_RUN_IFELSE(
[AC_LANG_PROGRAM(
[[#include <unistd.h>
]],
[[int result = 0;
if (!truncate ("conftest.tmp/", 2))
result |= 1;
return result;
]])
],
[gl_cv_func_truncate_works=yes],
[gl_cv_func_truncate_works=no],
[case "$host_os" in
# Guess yes on Linux systems.
linux-* | linux) gl_cv_func_truncate_works="guessing yes" ;;
# Guess yes on glibc systems.
*-gnu* | gnu*) gl_cv_func_truncate_works="guessing yes" ;;
# Guess no on AIX systems.
aix*) gl_cv_func_truncate_works="guessing no" ;;
# If we don't know, obey --enable-cross-guesses.
*) gl_cv_func_truncate_works="$gl_cross_guess_normal" ;;
esac
])
rm -f conftest.tmp
])
case "$gl_cv_func_truncate_works" in
*yes) ;;
*)
AC_DEFINE([TRUNCATE_TRAILING_SLASH_BUG], [1],
[Define to 1 if truncate mishandles trailing slash.])
REPLACE_TRUNCATE=1
;;
esac
fi
else
HAVE_DECL_TRUNCATE=0
case "$gl_cv_onwards_func_truncate" in
dnl Avoid a conflict with the 'truncate' in libc.
yes | future*) REPLACE_TRUNCATE=1 ;;
esac
fi
])
# Prerequisites of lib/truncate.c.
AC_DEFUN([gl_PREREQ_TRUNCATE], [:])
|
