Function strerror

libs/libc/string/lib_strerror.c:374–413

 ****************************************************************************/

FAR char *strerror(int errnum)
{
#ifdef CONFIG_LIBC_STRERROR_ERRNUM
  static char s_err[STRERROR_BUFSIZE];
#endif
#ifdef CONFIG_LIBC_STRERROR
  int ndxlow = 0;
  int ndxhi  = NERRNO_STRS - 1;
  int ndxmid;

  do
    {
      ndxmid = (ndxlow + ndxhi) >> 1;
      if (errnum > g_errnomap[ndxmid].errnum)
        {
          ndxlow = ndxmid + 1;
        }
      else if (errnum < g_errnomap[ndxmid].errnum)
        {
          ndxhi = ndxmid - 1;
        }
      else
        {
          return g_errnomap[ndxmid].str;
        }
    }
  while (ndxlow <= ndxhi);
#endif
#ifdef CONFIG_LIBC_STRERROR_ERRNUM
  if (snprintf(s_err, sizeof(s_err), STRERROR_UNKNOWN " %d", errnum)
      < sizeof(s_err))
    {
      return s_err;
    }
#elif !defined(CONFIG_LIBC_STRERROR)
  UNUSED(errnum);
#endif

  return STRERROR_UNKNOWN;
}