m4/sys_select_h.m4

   1 # sys_select_h.m4 serial 20
   2 dnl Copyright (C) 2006-2017 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_HEADER_SYS_SELECT],
   8 [
   9   AC_REQUIRE([AC_C_RESTRICT])
  10   AC_REQUIRE([gl_SYS_SELECT_H_DEFAULTS])
  11   AC_CACHE_CHECK([whether <sys/select.h> is self-contained],
  12     [gl_cv_header_sys_select_h_selfcontained],
  13     [
  14       dnl Test against two bugs:
  15       dnl 1. On many platforms, <sys/select.h> assumes prior inclusion of
  16       dnl    <sys/types.h>.
  17       dnl 2. On OSF/1 4.0, <sys/select.h> provides only a forward declaration
  18       dnl    of 'struct timeval', and no definition of this type.
  19       AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <sys/select.h>]],
  20                                          [[struct timeval b;]])],
  21         [gl_cv_header_sys_select_h_selfcontained=yes],
  22         [gl_cv_header_sys_select_h_selfcontained=no])
  23       dnl Test against another bug:
  24       dnl 3. On Solaris 10, <sys/select.h> provides an FD_ZERO implementation
  25       dnl    that relies on memset(), but without including <string.h>.
  26       if test $gl_cv_header_sys_select_h_selfcontained = yes; then
  27         AC_COMPILE_IFELSE(
  28           [AC_LANG_PROGRAM([[#include <sys/select.h>]],
  29                            [[int memset; int bzero;]])
  30           ],
  31           [AC_LINK_IFELSE(
  32              [AC_LANG_PROGRAM([[#include <sys/select.h>]], [[
  33                   #undef memset
  34                   #define memset nonexistent_memset
  35                   extern
  36                   #ifdef __cplusplus
  37                   "C"
  38                   #endif
  39                   void *memset (void *, int, unsigned long);
  40                   #undef bzero
  41                   #define bzero nonexistent_bzero
  42                   extern
  43                   #ifdef __cplusplus
  44                   "C"
  45                   #endif
  46                   void bzero (void *, unsigned long);
  47                   fd_set fds;
  48                   FD_ZERO (&fds);
  49                 ]])
  50              ],
  51              [],
  52              [gl_cv_header_sys_select_h_selfcontained=no])
  53           ])
  54       fi
  55     ])
  56   dnl <sys/select.h> is always overridden, because of GNULIB_POSIXCHECK.
  57   gl_CHECK_NEXT_HEADERS([sys/select.h])
  58   if test $ac_cv_header_sys_select_h = yes; then
  59     HAVE_SYS_SELECT_H=1
  60   else
  61     HAVE_SYS_SELECT_H=0
  62   fi
  63   AC_SUBST([HAVE_SYS_SELECT_H])
  64   gl_PREREQ_SYS_H_WINSOCK2
  65
  66   dnl Check for declarations of anything we want to poison if the
  67   dnl corresponding gnulib module is not in use.
  68   gl_WARN_ON_USE_PREPARE([[
  69 /* Some systems require prerequisite headers.  */
  70 #include <sys/types.h>
  71 #if !(defined __GLIBC__ && !defined __UCLIBC__) && HAVE_SYS_TIME_H
  72 # include <sys/time.h>
  73 #endif
  74 #include <sys/select.h>
  75     ]], [pselect select])
  76 ])
  77
  78 AC_DEFUN([gl_SYS_SELECT_MODULE_INDICATOR],
  79 [
  80   dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
  81   AC_REQUIRE([gl_SYS_SELECT_H_DEFAULTS])
  82   gl_MODULE_INDICATOR_SET_VARIABLE([$1])
  83   dnl Define it also as a C macro, for the benefit of the unit tests.
  84   gl_MODULE_INDICATOR_FOR_TESTS([$1])
  85 ])
  86
  87 AC_DEFUN([gl_SYS_SELECT_H_DEFAULTS],
  88 [
  89   GNULIB_PSELECT=0; AC_SUBST([GNULIB_PSELECT])
  90   GNULIB_SELECT=0; AC_SUBST([GNULIB_SELECT])
  91   dnl Assume proper GNU behavior unless another module says otherwise.
  92   HAVE_PSELECT=1; AC_SUBST([HAVE_PSELECT])
  93   REPLACE_PSELECT=0; AC_SUBST([REPLACE_PSELECT])
  94   REPLACE_SELECT=0; AC_SUBST([REPLACE_SELECT])
  95 ])