Function my_strerror

strings/my_vsnprintf.c:908–966

*/

const char* my_strerror(char *buf, size_t len, int nr)
{
  char *msg= NULL;

  buf[0]= '\0';                                  /* failsafe */

  if (nr <= 0)
  {
    strmake(buf, (nr == 0 ?
                  "Internal error/check (Not system error)" :
                  "Internal error < 0 (Not system error)"),
            len-1);
    return buf;
  }

  /*
    These (handler-) error messages are shared by perror, as required
    by the principle of least surprise.
  */
  if ((nr >= HA_ERR_FIRST) && (nr <= HA_ERR_LAST))
  {
    msg= (char *) handler_error_messages[nr - HA_ERR_FIRST];
    strmake(buf, msg, len - 1);
  }
  else
  {
    /*
      On Windows, do things the Windows way. On a system that supports both
      the GNU and the XSI variant, use whichever was configured (GNU); if
      this choice is not advertised, use the default (POSIX/XSI).  Testing
      for __GNUC__ is not sufficient to determine whether this choice exists.
    */
#if defined(_WIN32)
    strerror_s(buf, len, nr);
#elif ((defined _POSIX_C_SOURCE && (_POSIX_C_SOURCE >= 200112L)) ||    \
       (defined _XOPEN_SOURCE   && (_XOPEN_SOURCE >= 600)))      &&    \
      ! defined _GNU_SOURCE
    strerror_r(nr, buf, len);             /* I can build with or without GNU */
#elif defined(__GLIBC__) && defined (_GNU_SOURCE)
    char *r= strerror_r(nr, buf, len);
    if (r != buf)                         /* Want to help, GNU? */
      strmake(buf, r, len - 1);           /* Then don't. */
#else
    strerror_r(nr, buf, len);
#endif

#ifdef __APPLE__
    delete_colon_char(buf);
#endif
  }

  /*
    strerror() return values are implementation-dependent, so let's
    be pragmatic.
  */
  if (!buf[0])
    strmake(buf, "unknown error", len - 1);
  return buf;