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[gnutls:gnutls.git] / gl / m4 / select.m4
1 # select.m4 serial 7
2 dnl Copyright (C) 2009-2012 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_SELECT],
8 [
9   AC_REQUIRE([gl_HEADER_SYS_SELECT])
10   AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
11   AC_REQUIRE([gl_SOCKETS])
12   if test "$ac_cv_header_winsock2_h" = yes; then
13     REPLACE_SELECT=1
14   else
15     dnl On Interix 3.5, select(0, NULL, NULL, NULL, timeout) fails with error
16     dnl EFAULT.
17     AC_CHECK_HEADERS_ONCE([sys/select.h])
18     AC_CACHE_CHECK([whether select supports a 0 argument],
19       [gl_cv_func_select_supports0],
20       [
21         AC_RUN_IFELSE([AC_LANG_SOURCE([[
22 #include <sys/types.h>
23 #include <sys/time.h>
24 #if HAVE_SYS_SELECT_H
25 #include <sys/select.h>
26 #endif
27 int main ()
28 {
29   struct timeval timeout;
30   timeout.tv_sec = 0;
31   timeout.tv_usec = 5;
32   return select (0, (fd_set *)0, (fd_set *)0, (fd_set *)0, &timeout) < 0;
33 }]])], [gl_cv_func_select_supports0=yes], [gl_cv_func_select_supports0=no],
34           [
35 changequote(,)dnl
36            case "$host_os" in
37                        # Guess no on Interix.
38              interix*) gl_cv_func_select_supports0="guessing no";;
39                        # Guess yes otherwise.
40              *)        gl_cv_func_select_supports0="guessing yes";;
41            esac
42 changequote([,])dnl
43           ])
44       ])
45     case "$gl_cv_func_select_supports0" in
46       *yes) ;;
47       *) REPLACE_SELECT=1 ;;
48     esac
49
50     dnl On FreeBSD 8.2, select() doesn't always reject bad fds.
51     AC_CACHE_CHECK([whether select detects invalid fds],
52       [gl_cv_func_select_detects_ebadf],
53       [
54         AC_RUN_IFELSE([AC_LANG_PROGRAM([[
55 #include <sys/types.h>
56 #include <sys/time.h>
57 #if HAVE_SYS_SELECT_H
58 # include <sys/select.h>
59 #endif
60 #include <unistd.h>
61 #include <errno.h>
62 ]],[[
63   fd_set set;
64   dup2(0, 16);
65   FD_ZERO(&set);
66   FD_SET(16, &set);
67   close(16);
68   struct timeval timeout;
69   timeout.tv_sec = 0;
70   timeout.tv_usec = 5;
71   return select (17, &set, NULL, NULL, &timeout) != -1 || errno != EBADF;
72 ]])], [gl_cv_func_select_detects_ebadf=yes],
73       [gl_cv_func_select_detects_ebadf=no],
74           [
75            case "$host_os" in
76                     # Guess yes on glibc systems.
77             *-gnu*) gl_cv_func_select_detects_ebadf="guessing yes" ;;
78                     # If we don't know, assume the worst.
79             *)      gl_cv_func_select_detects_ebadf="guessing no" ;;
80            esac
81           ])
82       ])
83     case $gl_cv_func_select_detects_ebadf in
84       *yes) ;;
85       *) REPLACE_SELECT=1 ;;
86     esac
87   fi
88
89   dnl Determine the needed libraries.
90   LIB_SELECT="$LIBSOCKET"
91   if test $REPLACE_SELECT = 1; then
92     case "$host_os" in
93       mingw*)
94         dnl On the MSVC platform, the function MsgWaitForMultipleObjects
95         dnl (used in lib/select.c) requires linking with -luser32. On mingw,
96         dnl it is implicit.
97         AC_LINK_IFELSE(
98           [AC_LANG_SOURCE([[
99 #define WIN32_LEAN_AND_MEAN
100 #include <windows.h>
101 int
102 main ()
103 {
104   MsgWaitForMultipleObjects (0, NULL, 0, 0, 0);
105   return 0;
106 }]])],
107           [],
108           [LIB_SELECT="$LIB_SELECT -luser32"])
109         ;;
110     esac
111   fi
112   AC_SUBST([LIB_SELECT])
113 ])