gnulib/import/m4/strerror.m4

   1 # strerror.m4 serial 17
   2 dnl Copyright (C) 2002, 2007-2016 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_STRERROR],
   8 [
   9   AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
  10   AC_REQUIRE([gl_HEADER_ERRNO_H])
  11   AC_REQUIRE([gl_FUNC_STRERROR_0])
  12   AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
  13   m4_ifdef([gl_FUNC_STRERROR_R_WORKS], [
  14     AC_REQUIRE([gl_FUNC_STRERROR_R_WORKS])
  15   ])
  16   if test "$ERRNO_H:$REPLACE_STRERROR_0" = :0; then
  17     AC_CACHE_CHECK([for working strerror function],
  18      [gl_cv_func_working_strerror],
  19      [AC_RUN_IFELSE(
  20         [AC_LANG_PROGRAM(
  21            [[#include <string.h>
  22            ]],
  23            [[if (!*strerror (-2)) return 1;]])],
  24         [gl_cv_func_working_strerror=yes],
  25         [gl_cv_func_working_strerror=no],
  26         [case "$host_os" in
  27                    # Guess yes on glibc systems.
  28            *-gnu*) gl_cv_func_working_strerror="guessing yes" ;;
  29                    # If we don't know, assume the worst.
  30            *)      gl_cv_func_working_strerror="guessing no" ;;
  31          esac
  32         ])
  33     ])
  34     case "$gl_cv_func_working_strerror" in
  35       *yes) ;;
  36       *)
  37         dnl The system's strerror() fails to return a string for out-of-range
  38         dnl integers. Replace it.
  39         REPLACE_STRERROR=1
  40         ;;
  41     esac
  42     m4_ifdef([gl_FUNC_STRERROR_R_WORKS], [
  43       dnl If the system's strerror_r or __xpg_strerror_r clobbers strerror's
  44       dnl buffer, we must replace strerror.
  45       case "$gl_cv_func_strerror_r_works" in
  46         *no) REPLACE_STRERROR=1 ;;
  47       esac
  48     ])
  49   else
  50     dnl The system's strerror() cannot know about the new errno values we add
  51     dnl to <errno.h>, or any fix for strerror(0). Replace it.
  52     REPLACE_STRERROR=1
  53   fi
  54 ])
  55
  56 dnl Detect if strerror(0) passes (that is, does not set errno, and does not
  57 dnl return a string that matches strerror(-1)).
  58 AC_DEFUN([gl_FUNC_STRERROR_0],
  59 [
  60   AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
  61   REPLACE_STRERROR_0=0
  62   AC_CACHE_CHECK([whether strerror(0) succeeds],
  63    [gl_cv_func_strerror_0_works],
  64    [AC_RUN_IFELSE(
  65       [AC_LANG_PROGRAM(
  66          [[#include <string.h>
  67            #include <errno.h>
  68          ]],
  69          [[int result = 0;
  70            char *str;
  71            errno = 0;
  72            str = strerror (0);
  73            if (!*str) result |= 1;
  74            if (errno) result |= 2;
  75            if (strstr (str, "nknown") || strstr (str, "ndefined"))
  76              result |= 4;
  77            return result;]])],
  78       [gl_cv_func_strerror_0_works=yes],
  79       [gl_cv_func_strerror_0_works=no],
  80       [case "$host_os" in
  81                  # Guess yes on glibc systems.
  82          *-gnu*) gl_cv_func_strerror_0_works="guessing yes" ;;
  83                  # If we don't know, assume the worst.
  84          *)      gl_cv_func_strerror_0_works="guessing no" ;;
  85        esac
  86       ])
  87   ])
  88   case "$gl_cv_func_strerror_0_works" in
  89     *yes) ;;
  90     *)
  91       REPLACE_STRERROR_0=1
  92       AC_DEFINE([REPLACE_STRERROR_0], [1], [Define to 1 if strerror(0)
  93         does not return a message implying success.])
  94       ;;
  95   esac
  96 ])