init_syntax_once ()
{
   register int c;
   static int done = 0;

   if (done)
     return;
   bzero (re_syntax_table, sizeof re_syntax_table);

   for (c = 0; c < CHAR_SET_SIZE; ++c)
     if (ISALNUM (c))
	re_syntax_table[c] = Sword;

   re_syntax_table['_'] = Sword;

   done = 1;
}
The software does not check the return value from a method or function, which can prevent it from detecting unexpected states and conditions.