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Diffstat (limited to 'gl/m4/select.m4')
| -rw-r--r-- | gl/m4/select.m4 | 122 |
1 files changed, 122 insertions, 0 deletions
diff --git a/gl/m4/select.m4 b/gl/m4/select.m4 new file mode 100644 index 0000000..88861af --- /dev/null +++ b/gl/m4/select.m4 @@ -0,0 +1,122 @@ +# select.m4 serial 15 +dnl Copyright (C) 2009-2023 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_SELECT], +[ + AC_REQUIRE([gl_SYS_SELECT_H]) + AC_REQUIRE([AC_C_RESTRICT]) + AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles + AC_REQUIRE([gl_SOCKETS]) + if test "$ac_cv_header_winsock2_h" = yes; then + REPLACE_SELECT=1 + else + dnl On Interix 3.5, select(0, NULL, NULL, NULL, timeout) fails with error + dnl EFAULT. + AC_CHECK_HEADERS_ONCE([sys/select.h]) + AC_CACHE_CHECK([whether select supports a 0 argument], + [gl_cv_func_select_supports0], + [ + AC_RUN_IFELSE([AC_LANG_SOURCE([[ +#include <sys/types.h> +#include <sys/time.h> +#if HAVE_SYS_SELECT_H +#include <sys/select.h> +#endif +int main () +{ + struct timeval timeout; + timeout.tv_sec = 0; + timeout.tv_usec = 5; + return select (0, (fd_set *)0, (fd_set *)0, (fd_set *)0, &timeout) < 0; +}]])], [gl_cv_func_select_supports0=yes], [gl_cv_func_select_supports0=no], + [ +changequote(,)dnl + case "$host_os" in + # Guess no on Interix. + interix*) gl_cv_func_select_supports0="guessing no";; + # Guess yes otherwise. + *) gl_cv_func_select_supports0="guessing yes";; + esac +changequote([,])dnl + ]) + ]) + case "$gl_cv_func_select_supports0" in + *yes) ;; + *) REPLACE_SELECT=1 ;; + esac + + dnl On FreeBSD 8.2, select() doesn't always reject bad fds. + AC_CACHE_CHECK([whether select detects invalid fds], + [gl_cv_func_select_detects_ebadf], + [ + AC_RUN_IFELSE([AC_LANG_PROGRAM([[ +#include <sys/types.h> +#include <sys/time.h> +#if HAVE_SYS_SELECT_H +# include <sys/select.h> +#endif +#include <unistd.h> +#include <errno.h> +]GL_MDA_DEFINES], +[[ + fd_set set; + dup2(0, 16); + FD_ZERO(&set); + FD_SET(16, &set); + close(16); + struct timeval timeout; + timeout.tv_sec = 0; + timeout.tv_usec = 5; + return select (17, &set, NULL, NULL, &timeout) != -1 || errno != EBADF; +]])], [gl_cv_func_select_detects_ebadf=yes], + [gl_cv_func_select_detects_ebadf=no], + [ + case "$host_os" in + # Guess yes on Linux systems. + linux-* | linux) gl_cv_func_select_detects_ebadf="guessing yes" ;; + # Guess yes on systems that emulate the Linux system calls. + midipix*) gl_cv_func_select_detects_ebadf="guessing yes" ;; + # Guess yes on glibc systems. + *-gnu* | gnu*) gl_cv_func_select_detects_ebadf="guessing yes" ;; + # If we don't know, obey --enable-cross-guesses. + *) gl_cv_func_select_detects_ebadf="$gl_cross_guess_normal" ;; + esac + ]) + ]) + case $gl_cv_func_select_detects_ebadf in + *yes) ;; + *) REPLACE_SELECT=1 ;; + esac + fi + + dnl Determine the needed libraries. + SELECT_LIB="$LIBSOCKET" + if test $REPLACE_SELECT = 1; then + case "$host_os" in + mingw*) + dnl On the MSVC platform, the function MsgWaitForMultipleObjects + dnl (used in lib/select.c) requires linking with -luser32. On mingw, + dnl it is implicit. + AC_LINK_IFELSE( + [AC_LANG_SOURCE([[ +#define WIN32_LEAN_AND_MEAN +#include <windows.h> +int +main () +{ + MsgWaitForMultipleObjects (0, NULL, 0, 0, 0); + return 0; +}]])], + [], + [SELECT_LIB="$SELECT_LIB -luser32"]) + ;; + esac + fi + AC_SUBST([SELECT_LIB]) + dnl For backward compatibility. + LIB_SELECT="$LIB_SELECT" + AC_SUBST([LIB_SELECT]) +]) |