# strsignal.m4 serial 8

dnl Copyright (C) 2008-2014 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_STRSIGNAL],

[

  dnl Persuade glibc <string.h> to declare strsignal().

  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])

  AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])

  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles

  AC_CHECK_DECLS_ONCE([strsignal])

  if test $ac_cv_have_decl_strsignal = no; then

    HAVE_DECL_STRSIGNAL=0

  fi

  AC_CHECK_FUNCS([strsignal])

  if test $ac_cv_func_strsignal = yes; then

    HAVE_STRSIGNAL=1

    dnl Check if strsignal behaves reasonably for out-of-range signal numbers.

    dnl On Solaris it returns NULL; on AIX 5.1 it returns (char *) -1.

    AC_CACHE_CHECK([whether strsignal always returns a string],

      [gl_cv_func_working_strsignal],

      [AC_RUN_IFELSE(

         [AC_LANG_PROGRAM(

            [[#include <string.h>

#include <unistd.h> /* NetBSD 5.0 declares it in wrong header. */

            ]],

            [[int result = 0;

              char *s = strsignal (-1);

              if (s == (char *) 0)

                result |= 1;

              if (s == (char *) -1)

                result |= 2;

              return result;

            ]])],

         [gl_cv_func_working_strsignal=yes],

         [gl_cv_func_working_strsignal=no],

         [case "$host_os" in

            solaris* | aix*) gl_cv_func_working_strsignal=no;;

            *)               gl_cv_func_working_strsignal="guessing yes";;

          esac])])

    if test "$gl_cv_func_working_strsignal" = no; then

      REPLACE_STRSIGNAL=1

    fi

  else

    HAVE_STRSIGNAL=0

  fi

])

# Prerequisites of lib/strsignal.c.

AC_DEFUN([gl_PREREQ_STRSIGNAL], [

  AC_CHECK_HEADERS_ONCE([unistd.h])

  AC_REQUIRE([AC_DECL_SYS_SIGLIST])

  AC_CHECK_DECLS([_sys_siglist], [], [], [[#include <signal.h>]])

])