# strerror_r.m4 serial 20

dnl Copyright (C) 2002, 2007-2020 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_STRERROR_R],

[

  AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])

  AC_REQUIRE([gl_FUNC_STRERROR_R_WORKS])

  dnl Persuade Solaris <string.h> to declare strerror_r().

  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])

  dnl Some systems don't declare strerror_r() if _THREAD_SAFE and _REENTRANT

  dnl are not defined.

  AC_CHECK_DECLS_ONCE([strerror_r])

  if test $ac_cv_have_decl_strerror_r = no; then

    HAVE_DECL_STRERROR_R=0

  fi

  if test $ac_cv_func_strerror_r = yes; then

    if test "$ERRNO_H:$REPLACE_STRERROR_0" = :0; then

      if test $gl_cv_func_strerror_r_posix_signature = yes; then

        case "$gl_cv_func_strerror_r_works" in

          dnl The system's strerror_r has bugs.  Replace it.

          *no) REPLACE_STRERROR_R=1 ;;

        esac

      else

        dnl The system's strerror_r() has a wrong signature. Replace it.

        REPLACE_STRERROR_R=1

      fi

    else

      dnl The system's strerror_r() cannot know about the new errno values we

      dnl add to <errno.h>, or any fix for strerror(0). Replace it.

      REPLACE_STRERROR_R=1

    fi

  fi

])

# Prerequisites of lib/strerror_r.c.

AC_DEFUN([gl_PREREQ_STRERROR_R], [

  dnl glibc >= 2.3.4 and cygwin 1.7.9 have a function __xpg_strerror_r.

  AC_CHECK_FUNCS_ONCE([__xpg_strerror_r])

  AC_CHECK_FUNCS_ONCE([catgets])

  AC_CHECK_FUNCS_ONCE([snprintf])

])

# Detect if strerror_r works, but without affecting whether a replacement

# strerror_r will be used.

AC_DEFUN([gl_FUNC_STRERROR_R_WORKS],

[

  AC_REQUIRE([gl_HEADER_ERRNO_H])

  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles

  AC_REQUIRE([gl_FUNC_STRERROR_0])

  AC_CHECK_FUNCS_ONCE([strerror_r])

  if test $ac_cv_func_strerror_r = yes; then

    if test "$ERRNO_H:$REPLACE_STRERROR_0" = :0; then

      dnl The POSIX prototype is:  int strerror_r (int, char *, size_t);

      dnl glibc, Cygwin:           char *strerror_r (int, char *, size_t);

      dnl AIX 5.1, OSF/1 5.1:      int strerror_r (int, char *, int);

      AC_CACHE_CHECK([for strerror_r with POSIX signature],

        [gl_cv_func_strerror_r_posix_signature],

        [AC_COMPILE_IFELSE(

           [AC_LANG_PROGRAM(

              [[#include <string.h>

                int strerror_r (int, char *, size_t);

              ]],

              [])],

           [gl_cv_func_strerror_r_posix_signature=yes],

           [gl_cv_func_strerror_r_posix_signature=no])

        ])

      if test $gl_cv_func_strerror_r_posix_signature = yes; then

        dnl AIX 6.1 strerror_r fails by returning -1, not an error number.

        dnl HP-UX 11.31 strerror_r always fails when the buffer length argument

        dnl is less than 80.

        dnl FreeBSD 8.s strerror_r claims failure on 0

        dnl Mac OS X 10.5 strerror_r treats 0 like -1

        dnl Solaris 10 strerror_r corrupts errno on failure

        AC_CACHE_CHECK([whether strerror_r works],

          [gl_cv_func_strerror_r_works],

          [AC_RUN_IFELSE(

             [AC_LANG_PROGRAM(

                [[#include <errno.h>

                  #include <string.h>

                ]],

                [[int result = 0;

                  char buf[79];

                  if (strerror_r (EACCES, buf, 0) < 0)

                    result |= 1;

                  errno = 0;

                  if (strerror_r (EACCES, buf, sizeof buf) != 0)

                    result |= 2;

                  strcpy (buf, "Unknown");

                  if (strerror_r (0, buf, sizeof buf) != 0)

                    result |= 4;

                  if (errno)

                    result |= 8;

                  if (strstr (buf, "nknown") || strstr (buf, "ndefined"))

                    result |= 0x10;

                  errno = 0;

                  *buf = 0;

                  if (strerror_r (-3, buf, sizeof buf) < 0)

                    result |= 0x20;

                  if (errno)

                    result |= 0x40;

                  if (!*buf)

                    result |= 0x80;

                  return result;

                ]])],

             [gl_cv_func_strerror_r_works=yes],

             [gl_cv_func_strerror_r_works=no],

             [

changequote(,)dnl

              case "$host_os" in

                       # Guess no on AIX.

                aix*)  gl_cv_func_strerror_r_works="guessing no";;

                       # Guess no on HP-UX.

                hpux*) gl_cv_func_strerror_r_works="guessing no";;

                       # Guess no on BSD variants.

                *bsd*)  gl_cv_func_strerror_r_works="guessing no";;

                       # Guess yes otherwise.

                *)     gl_cv_func_strerror_r_works="guessing yes";;

              esac

changequote([,])dnl

             ])

          ])

      else

        dnl The system's strerror() has a wrong signature.

        dnl glibc >= 2.3.4 and cygwin 1.7.9 have a function __xpg_strerror_r.

        AC_CHECK_FUNCS_ONCE([__xpg_strerror_r])

        dnl In glibc < 2.14, __xpg_strerror_r does not populate buf on failure.

        dnl In cygwin < 1.7.10, __xpg_strerror_r clobbers strerror's buffer.

        if test $ac_cv_func___xpg_strerror_r = yes; then

          AC_CACHE_CHECK([whether __xpg_strerror_r works],

            [gl_cv_func_strerror_r_works],

            [AC_RUN_IFELSE(

               [AC_LANG_PROGRAM(

                  [[#include <errno.h>

                    #include <string.h>

                    extern

                    #ifdef __cplusplus

                    "C"

                    #endif

                    int __xpg_strerror_r(int, char *, size_t);

                  ]],

                  [[int result = 0;

                    char buf[256] = "^";

                    char copy[256];

                    char *str = strerror (-1);

                    strcpy (copy, str);

                    if (__xpg_strerror_r (-2, buf, 1) == 0)

                      result |= 1;

                    if (*buf)

                      result |= 2;

                    __xpg_strerror_r (-2, buf, 256);

                    if (strcmp (str, copy))

                      result |= 4;

                    return result;

                  ]])],

               [gl_cv_func_strerror_r_works=yes],

               [gl_cv_func_strerror_r_works=no],

               [dnl Guess no on all platforms that have __xpg_strerror_r,

                dnl at least until fixed glibc and cygwin are more common.

                gl_cv_func_strerror_r_works="$gl_cross_guess_normal"

               ])

            ])

        fi

      fi

    fi

  fi

])