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#serial 12
dnl Copyright (C) 2002, 2005, 2007, 2009-2011 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_DUP2],
[
AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
AC_REQUIRE([AC_CANONICAL_HOST])
AC_CHECK_FUNCS_ONCE([dup2 fcntl])
if test $ac_cv_func_dup2 = no; then
HAVE_DUP2=0
AC_LIBOBJ([dup2])
else
AC_CACHE_CHECK([whether dup2 works], [gl_cv_func_dup2_works],
[AC_RUN_IFELSE([
AC_LANG_PROGRAM([[#include <unistd.h>
#include <fcntl.h>
#include <errno.h>]],
[int result = 0;
#if HAVE_FCNTL
if (fcntl (1, F_SETFD, FD_CLOEXEC) == -1)
result |= 1;
#endif HAVE_FCNTL
if (dup2 (1, 1) == 0)
result |= 2;
#if HAVE_FCNTL
if (fcntl (1, F_GETFD) != FD_CLOEXEC)
result |= 4;
#endif
close (0);
if (dup2 (0, 0) != -1)
result |= 8;
/* Many gnulib modules require POSIX conformance of EBADF. */
if (dup2 (2, 1000000) == -1 && errno != EBADF)
result |= 16;
return result;
])
],
[gl_cv_func_dup2_works=yes], [gl_cv_func_dup2_works=no],
[case "$host_os" in
mingw*) # on this platform, dup2 always returns 0 for success
gl_cv_func_dup2_works=no;;
cygwin*) # on cygwin 1.5.x, dup2(1,1) returns 0
gl_cv_func_dup2_works=no;;
linux*) # On linux between 2008-07-27 and 2009-05-11, dup2 of a
# closed fd may yield -EBADF instead of -1 / errno=EBADF.
gl_cv_func_dup2_works=no;;
freebsd*) # on FreeBSD 6.1, dup2(1,1000000) gives EMFILE, not EBADF.
gl_cv_func_dup2_works=no;;
haiku*) # on Haiku alpha 2, dup2(1, 1) resets FD_CLOEXEC.
gl_cv_func_dup2_works=no;;
*) gl_cv_func_dup2_works=yes;;
esac])
])
if test "$gl_cv_func_dup2_works" = no; then
gl_REPLACE_DUP2
fi
fi
])
AC_DEFUN([gl_REPLACE_DUP2],
[
AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
if test $ac_cv_func_dup2 = yes; then
REPLACE_DUP2=1
fi
AC_LIBOBJ([dup2])
])
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