1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
|
#serial 20
dnl Copyright (C) 2002, 2005, 2007, 2009-2014 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([getdtablesize])
m4_ifdef([gl_FUNC_DUP2_OBSOLETE], [
AC_CHECK_FUNCS_ONCE([dup2])
if test $ac_cv_func_dup2 = no; then
HAVE_DUP2=0
fi
], [
AC_DEFINE([HAVE_DUP2], [1], [Define to 1 if you have the 'dup2' function.])
])
if test $HAVE_DUP2 = 1; then
AC_CACHE_CHECK([whether dup2 works], [gl_cv_func_dup2_works],
[AC_RUN_IFELSE([
AC_LANG_PROGRAM([[#include <unistd.h>
#include <fcntl.h>
#include <errno.h>]],
[int result = 0;
#ifdef HAVE_GETDTABLESIZE
int bad_fd = getdtablesize ();
#else
int bad_fd = 1000000;
#endif
#ifdef FD_CLOEXEC
if (fcntl (1, F_SETFD, FD_CLOEXEC) == -1)
result |= 1;
#endif
if (dup2 (1, 1) == 0)
result |= 2;
#ifdef FD_CLOEXEC
if (fcntl (1, F_GETFD) != FD_CLOEXEC)
result |= 4;
#endif
close (0);
if (dup2 (0, 0) != -1)
result |= 8;
/* Many gnulib modules require POSIX conformance of EBADF. */
if (dup2 (2, bad_fd) == -1 && errno != EBADF)
result |= 16;
/* Flush out some cygwin core dumps. */
if (dup2 (2, -1) != -1 || errno != EBADF)
result |= 32;
dup2 (2, 255);
dup2 (2, 256);
return result;
])
],
[gl_cv_func_dup2_works=yes], [gl_cv_func_dup2_works=no],
[case "$host_os" in
mingw*) # on this platform, dup2 always returns 0 for success
gl_cv_func_dup2_works="guessing no" ;;
cygwin*) # on cygwin 1.5.x, dup2(1,1) returns 0
gl_cv_func_dup2_works="guessing 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="guessing no" ;;
aix* | freebsd*)
# on AIX 7.1 and FreeBSD 6.1, dup2 (1,toobig) gives EMFILE,
# not EBADF.
gl_cv_func_dup2_works="guessing no" ;;
haiku*) # on Haiku alpha 2, dup2(1, 1) resets FD_CLOEXEC.
gl_cv_func_dup2_works="guessing no" ;;
*) gl_cv_func_dup2_works="guessing yes" ;;
esac])
])
case "$gl_cv_func_dup2_works" in
*yes) ;;
*)
REPLACE_DUP2=1
AC_CHECK_FUNCS([setdtablesize])
;;
esac
fi
dnl Replace dup2() for supporting the gnulib-defined fchdir() function,
dnl to keep fchdir's bookkeeping up-to-date.
m4_ifdef([gl_FUNC_FCHDIR], [
gl_TEST_FCHDIR
if test $HAVE_FCHDIR = 0; then
if test $HAVE_DUP2 = 1; then
REPLACE_DUP2=1
fi
fi
])
])
# Prerequisites of lib/dup2.c.
AC_DEFUN([gl_PREREQ_DUP2], [])
|
