| 1 | # pselect.m4 serial 10
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| 2 | dnl Copyright (C) 2011-2022 Free Software Foundation, Inc.
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| 3 | dnl This file is free software; the Free Software Foundation
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| 4 | dnl gives unlimited permission to copy and/or distribute it,
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| 5 | dnl with or without modifications, as long as this notice is preserved.
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| 6 |
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| 7 | AC_DEFUN([gl_FUNC_PSELECT],
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| 8 | [
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| 9 | AC_REQUIRE([gl_SYS_SELECT_H])
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| 10 | AC_REQUIRE([AC_C_RESTRICT])
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| 11 | AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
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| 12 | AC_CHECK_FUNCS_ONCE([pselect])
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| 13 |
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| 14 | if test $ac_cv_func_pselect = yes; then
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| 15 | AC_CACHE_CHECK([whether signature of pselect conforms to POSIX],
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| 16 | [gl_cv_sig_pselect],
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| 17 | [AC_LINK_IFELSE(
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| 18 | [AC_LANG_PROGRAM(
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| 19 | [[#include <sys/select.h>
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| 20 | ]],
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| 21 | [[int (*p) (int, fd_set *, fd_set *, fd_set *restrict,
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| 22 | struct timespec const *restrict,
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| 23 | sigset_t const *restrict) = pselect;
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| 24 | return !p;]])],
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| 25 | [gl_cv_sig_pselect=yes],
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| 26 | [gl_cv_sig_pselect=no])])
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| 27 |
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| 28 | dnl On FreeBSD 8.2, pselect() doesn't always reject bad fds.
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| 29 | AC_CACHE_CHECK([whether pselect detects invalid fds],
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| 30 | [gl_cv_func_pselect_detects_ebadf],
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| 31 | [
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| 32 | AC_RUN_IFELSE([AC_LANG_PROGRAM([[
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| 33 | #include <sys/types.h>
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| 34 | #include <sys/time.h>
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| 35 | #if HAVE_SYS_SELECT_H
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| 36 | # include <sys/select.h>
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| 37 | #endif
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| 38 | #include <unistd.h>
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| 39 | #include <errno.h>
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| 40 | ]GL_MDA_DEFINES],
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| 41 | [[
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| 42 | fd_set set;
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| 43 | dup2(0, 16);
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| 44 | FD_ZERO(&set);
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| 45 | FD_SET(16, &set);
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| 46 | close(16);
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| 47 | struct timespec timeout;
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| 48 | timeout.tv_sec = 0;
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| 49 | timeout.tv_nsec = 5000;
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| 50 | return pselect (17, &set, NULL, NULL, &timeout, NULL) != -1 || errno != EBADF;
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| 51 | ]])], [gl_cv_func_pselect_detects_ebadf=yes],
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| 52 | [gl_cv_func_pselect_detects_ebadf=no],
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| 53 | [
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| 54 | case "$host_os" in
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| 55 | # Guess yes on Linux systems.
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| 56 | linux-* | linux) gl_cv_func_pselect_detects_ebadf="guessing yes" ;;
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| 57 | # Guess yes on glibc systems.
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| 58 | *-gnu* | gnu*) gl_cv_func_pselect_detects_ebadf="guessing yes" ;;
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| 59 | # If we don't know, obey --enable-cross-guesses.
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| 60 | *) gl_cv_func_pselect_detects_ebadf="$gl_cross_guess_normal" ;;
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| 61 | esac
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| 62 | ])
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| 63 | ])
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| 64 | case $gl_cv_func_pselect_detects_ebadf in
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| 65 | *yes) ;;
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| 66 | *) REPLACE_PSELECT=1 ;;
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| 67 | esac
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| 68 | fi
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| 69 |
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| 70 | if test $ac_cv_func_pselect = no || test $gl_cv_sig_pselect = no; then
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| 71 | REPLACE_PSELECT=1
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| 72 | fi
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| 73 | ])
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