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3d458a81 AW |
1 | # lseek.m4 serial 7 |
2 | dnl Copyright (C) 2007, 2009-2011 Free Software Foundation, Inc. | |
3 | dnl This file is free software; the Free Software Foundation | |
4 | dnl gives unlimited permission to copy and/or distribute it, | |
5 | dnl with or without modifications, as long as this notice is preserved. | |
6 | ||
7 | AC_DEFUN([gl_FUNC_LSEEK], | |
8 | [ | |
9 | AC_REQUIRE([gl_UNISTD_H_DEFAULTS]) | |
10 | AC_REQUIRE([AC_PROG_CC]) | |
11 | AC_CACHE_CHECK([whether lseek detects pipes], [gl_cv_func_lseek_pipe], | |
12 | [if test $cross_compiling = no; then | |
13 | AC_LINK_IFELSE([AC_LANG_PROGRAM([[ | |
14 | #include <sys/types.h> /* for off_t */ | |
15 | #include <stdio.h> /* for SEEK_CUR */ | |
16 | #include <unistd.h>]], [[ | |
17 | /* Exit with success only if stdin is seekable. */ | |
18 | return lseek (0, (off_t)0, SEEK_CUR) < 0; | |
19 | ]])], | |
20 | [if test -s conftest$ac_exeext \ | |
21 | && ./conftest$ac_exeext < conftest.$ac_ext \ | |
22 | && test 1 = "`echo hi \ | |
23 | | { ./conftest$ac_exeext; echo $?; cat >/dev/null; }`"; then | |
24 | gl_cv_func_lseek_pipe=yes | |
25 | else | |
26 | gl_cv_func_lseek_pipe=no | |
27 | fi], | |
28 | [gl_cv_func_lseek_pipe=no]) | |
29 | else | |
30 | AC_COMPILE_IFELSE([AC_LANG_SOURCE([[ | |
31 | #if ((defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__) || defined __BEOS__ | |
32 | /* mingw and BeOS mistakenly return 0 when trying to seek on pipes. */ | |
33 | Choke me. | |
34 | #endif]])], | |
35 | [gl_cv_func_lseek_pipe=yes], [gl_cv_func_lseek_pipe=no]) | |
36 | fi]) | |
37 | if test $gl_cv_func_lseek_pipe = no; then | |
38 | REPLACE_LSEEK=1 | |
39 | AC_DEFINE([LSEEK_PIPE_BROKEN], [1], | |
40 | [Define to 1 if lseek does not detect pipes.]) | |
41 | fi | |
42 | ]) |