| 1 | # select.m4 serial 7 |
| 2 | dnl Copyright (C) 2009-2014 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 | ]) |