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dnl Copyright (C) 2007 Free Software Foundation, Inc.
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dnl This file is free software; the Free Software Foundation
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dnl gives unlimited permission to copy and/or distribute it,
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dnl with or without modifications, as long as this notice is preserved.
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AC_DEFUN([gl_FUNC_LSEEK],
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AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
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AC_REQUIRE([AC_PROG_CC])
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AC_CACHE_CHECK([whether lseek detects pipes], [gl_cv_func_lseek_pipe],
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[if test $cross_compiling = no; then
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#include <sys/types.h> /* for off_t */
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#include <stdio.h> /* for SEEK_CUR */
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/* Exit with success only if stdin is seekable. */
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return lseek (0, (off_t)0, SEEK_CUR) < 0;
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[if test -s conftest$ac_exeext \
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&& ./conftest$ac_exeext < conftest.$ac_ext \
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&& { echo hi | ./conftest$ac_exeext; test $? = 1; }; then
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gl_cv_func_lseek_pipe=yes
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gl_cv_func_lseek_pipe=no
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[gl_cv_func_lseek_pipe=no])
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#if ((defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__) || defined __BEOS__
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/* mingw and BeOS mistakenly return 0 when trying to seek on pipes. */
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[gl_cv_func_lseek_pipe=yes], [gl_cv_func_lseek_pipe=no])
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if test $gl_cv_func_lseek_pipe = no; then
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AC_DEFUN([gl_REPLACE_LSEEK],
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AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
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AC_DEFINE([LSEEK_PIPE_BROKEN], [1],
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[Define to 1 if lseek does not detect pipes.])