#define _DT_ERROR (-2147483648)

/* is string a valid time? */
istimestr(tstr)
{
        local status = FALSE;

        if (isstring(tstr))
        {
                if (strlen(strfind(":", tstr)) > 0)
                {
                        status = (not(todstr(tstr) == _DT_ERROR) || not(todmsecstr(tstr) == _DT_ERROR));
                }
        }

        return(status);
}