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5e69ceb7 MW |
1 | #serial 20 |
2 | dnl Copyright (C) 2002, 2005, 2007, 2009-2014 Free Software Foundation, Inc. | |
3dac6181 AW |
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_DUP2], | |
8 | [ | |
9 | AC_REQUIRE([gl_UNISTD_H_DEFAULTS]) | |
10 | AC_REQUIRE([AC_CANONICAL_HOST]) | |
11 | m4_ifdef([gl_FUNC_DUP2_OBSOLETE], [ | |
12 | AC_CHECK_FUNCS_ONCE([dup2]) | |
13 | if test $ac_cv_func_dup2 = no; then | |
14 | HAVE_DUP2=0 | |
15 | fi | |
16 | ], [ | |
17 | AC_DEFINE([HAVE_DUP2], [1], [Define to 1 if you have the 'dup2' function.]) | |
18 | ]) | |
19 | if test $HAVE_DUP2 = 1; then | |
20 | AC_CACHE_CHECK([whether dup2 works], [gl_cv_func_dup2_works], | |
21 | [AC_RUN_IFELSE([ | |
22 | AC_LANG_PROGRAM([[#include <unistd.h> | |
23 | #include <fcntl.h> | |
24 | #include <errno.h>]], | |
25 | [int result = 0; | |
26 | #ifdef FD_CLOEXEC | |
27 | if (fcntl (1, F_SETFD, FD_CLOEXEC) == -1) | |
28 | result |= 1; | |
29 | #endif | |
30 | if (dup2 (1, 1) == 0) | |
31 | result |= 2; | |
32 | #ifdef FD_CLOEXEC | |
33 | if (fcntl (1, F_GETFD) != FD_CLOEXEC) | |
34 | result |= 4; | |
35 | #endif | |
36 | close (0); | |
37 | if (dup2 (0, 0) != -1) | |
38 | result |= 8; | |
39 | /* Many gnulib modules require POSIX conformance of EBADF. */ | |
40 | if (dup2 (2, 1000000) == -1 && errno != EBADF) | |
41 | result |= 16; | |
5e69ceb7 | 42 | /* Flush out some cygwin core dumps. */ |
3dac6181 AW |
43 | if (dup2 (2, -1) != -1 || errno != EBADF) |
44 | result |= 32; | |
5e69ceb7 MW |
45 | dup2 (2, 255); |
46 | dup2 (2, 256); | |
3dac6181 AW |
47 | return result; |
48 | ]) | |
49 | ], | |
50 | [gl_cv_func_dup2_works=yes], [gl_cv_func_dup2_works=no], | |
51 | [case "$host_os" in | |
52 | mingw*) # on this platform, dup2 always returns 0 for success | |
53 | gl_cv_func_dup2_works="guessing no" ;; | |
54 | cygwin*) # on cygwin 1.5.x, dup2(1,1) returns 0 | |
55 | gl_cv_func_dup2_works="guessing no" ;; | |
56 | linux*) # On linux between 2008-07-27 and 2009-05-11, dup2 of a | |
57 | # closed fd may yield -EBADF instead of -1 / errno=EBADF. | |
58 | gl_cv_func_dup2_works="guessing no" ;; | |
59 | freebsd*) # on FreeBSD 6.1, dup2(1,1000000) gives EMFILE, not EBADF. | |
60 | gl_cv_func_dup2_works="guessing no" ;; | |
61 | haiku*) # on Haiku alpha 2, dup2(1, 1) resets FD_CLOEXEC. | |
62 | gl_cv_func_dup2_works="guessing no" ;; | |
63 | *) gl_cv_func_dup2_works="guessing yes" ;; | |
64 | esac]) | |
65 | ]) | |
66 | case "$gl_cv_func_dup2_works" in | |
67 | *yes) ;; | |
68 | *) | |
69 | REPLACE_DUP2=1 | |
5e69ceb7 | 70 | AC_CHECK_FUNCS([setdtablesize]) |
3dac6181 AW |
71 | ;; |
72 | esac | |
73 | fi | |
74 | dnl Replace dup2() for supporting the gnulib-defined fchdir() function, | |
75 | dnl to keep fchdir's bookkeeping up-to-date. | |
76 | m4_ifdef([gl_FUNC_FCHDIR], [ | |
77 | gl_TEST_FCHDIR | |
78 | if test $HAVE_FCHDIR = 0; then | |
79 | if test $HAVE_DUP2 = 1; then | |
80 | REPLACE_DUP2=1 | |
81 | fi | |
82 | fi | |
83 | ]) | |
84 | ]) | |
85 | ||
86 | # Prerequisites of lib/dup2.c. | |
87 | AC_DEFUN([gl_PREREQ_DUP2], []) |