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.
7 AC_DEFUN([gl_FUNC_SELECT],
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 "$ac_cv_header_winsock2_h" = yes; then
15 dnl On Interix 3.5, select(0, NULL, NULL, NULL, timeout) fails with error
17 AC_CHECK_HEADERS_ONCE([sys/select.h])
18 AC_CACHE_CHECK([whether select supports a 0 argument],
19 [gl_cv_func_select_supports0],
21 AC_RUN_IFELSE([AC_LANG_SOURCE([[
22 #include <sys/types.h>
25 #include <sys/select.h>
29 struct timeval timeout;
32 return select (0, (fd_set *)0, (fd_set *)0, (fd_set *)0, &timeout) < 0;
33 }]])], [gl_cv_func_select_supports0=yes], [gl_cv_func_select_supports0=no],
37 # Guess no on Interix.
38 interix*) gl_cv_func_select_supports0="guessing no";;
39 # Guess yes otherwise.
40 *) gl_cv_func_select_supports0="guessing yes";;
45 case "$gl_cv_func_select_supports0" in
47 *) REPLACE_SELECT=1 ;;
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],
54 AC_RUN_IFELSE([AC_LANG_PROGRAM([[
55 #include <sys/types.h>
58 # include <sys/select.h>
68 struct timeval timeout;
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],
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" ;;
83 case $gl_cv_func_select_detects_ebadf in
85 *) REPLACE_SELECT=1 ;;
89 dnl Determine the needed libraries.
90 LIB_SELECT="$LIBSOCKET"
91 if test $REPLACE_SELECT = 1; then
94 dnl On the MSVC platform, the function MsgWaitForMultipleObjects
95 dnl (used in lib/select.c) requires linking with -luser32. On mingw,
99 #define WIN32_LEAN_AND_MEAN
104 MsgWaitForMultipleObjects (0, NULL, 0, 0, 0);
108 [LIB_SELECT="$LIB_SELECT -luser32"])
112 AC_SUBST([LIB_SELECT])