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96 lines
3.5 KiB
Plaintext
96 lines
3.5 KiB
Plaintext
# sys_select_h.m4 serial 20
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dnl Copyright (C) 2006-2021 Free Software Foundation, Inc.
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dnl This file is free software; the Free Software Foundation
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dnl gives unlimited permission to copy and/or distribute it,
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dnl with or without modifications, as long as this notice is preserved.
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AC_DEFUN([gl_HEADER_SYS_SELECT],
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[
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AC_REQUIRE([AC_C_RESTRICT])
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AC_REQUIRE([gl_SYS_SELECT_H_DEFAULTS])
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AC_CACHE_CHECK([whether <sys/select.h> is self-contained],
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[gl_cv_header_sys_select_h_selfcontained],
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[
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dnl Test against two bugs:
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dnl 1. On many platforms, <sys/select.h> assumes prior inclusion of
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dnl <sys/types.h>.
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dnl 2. On OSF/1 4.0, <sys/select.h> provides only a forward declaration
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dnl of 'struct timeval', and no definition of this type.
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AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <sys/select.h>]],
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[[struct timeval b;]])],
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[gl_cv_header_sys_select_h_selfcontained=yes],
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[gl_cv_header_sys_select_h_selfcontained=no])
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dnl Test against another bug:
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dnl 3. On Solaris 10, <sys/select.h> provides an FD_ZERO implementation
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dnl that relies on memset(), but without including <string.h>.
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if test $gl_cv_header_sys_select_h_selfcontained = yes; then
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AC_COMPILE_IFELSE(
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[AC_LANG_PROGRAM([[#include <sys/select.h>]],
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[[int memset; int bzero;]])
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],
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[AC_LINK_IFELSE(
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[AC_LANG_PROGRAM([[#include <sys/select.h>]], [[
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#undef memset
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#define memset nonexistent_memset
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extern
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#ifdef __cplusplus
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"C"
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#endif
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void *memset (void *, int, unsigned long);
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#undef bzero
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#define bzero nonexistent_bzero
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extern
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#ifdef __cplusplus
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"C"
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#endif
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void bzero (void *, unsigned long);
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fd_set fds;
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FD_ZERO (&fds);
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]])
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],
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[],
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[gl_cv_header_sys_select_h_selfcontained=no])
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])
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fi
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])
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dnl <sys/select.h> is always overridden, because of GNULIB_POSIXCHECK.
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gl_CHECK_NEXT_HEADERS([sys/select.h])
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if test $ac_cv_header_sys_select_h = yes; then
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HAVE_SYS_SELECT_H=1
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else
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HAVE_SYS_SELECT_H=0
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fi
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AC_SUBST([HAVE_SYS_SELECT_H])
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gl_PREREQ_SYS_H_WINSOCK2
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dnl Check for declarations of anything we want to poison if the
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dnl corresponding gnulib module is not in use.
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gl_WARN_ON_USE_PREPARE([[
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/* Some systems require prerequisite headers. */
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#include <sys/types.h>
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#if !(defined __GLIBC__ && !defined __UCLIBC__) && HAVE_SYS_TIME_H
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# include <sys/time.h>
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#endif
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#include <sys/select.h>
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]], [pselect select])
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])
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AC_DEFUN([gl_SYS_SELECT_MODULE_INDICATOR],
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[
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dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
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AC_REQUIRE([gl_SYS_SELECT_H_DEFAULTS])
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gl_MODULE_INDICATOR_SET_VARIABLE([$1])
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dnl Define it also as a C macro, for the benefit of the unit tests.
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gl_MODULE_INDICATOR_FOR_TESTS([$1])
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])
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AC_DEFUN([gl_SYS_SELECT_H_DEFAULTS],
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[
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GNULIB_PSELECT=0; AC_SUBST([GNULIB_PSELECT])
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GNULIB_SELECT=0; AC_SUBST([GNULIB_SELECT])
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dnl Assume proper GNU behavior unless another module says otherwise.
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HAVE_PSELECT=1; AC_SUBST([HAVE_PSELECT])
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REPLACE_PSELECT=0; AC_SUBST([REPLACE_PSELECT])
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REPLACE_SELECT=0; AC_SUBST([REPLACE_SELECT])
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])
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