Proble tokenizing string

Something is wrong in this function. I could have a string that ends with a '?' but it's still included for some reason. For example, "How are you?" It returns 'How', 'are', 'you?' Why does it include the question mark? Thanks.

Code:

vector<String> Split(bool uppercase = false, const char *delims =", .;:'!?@#$%^&*()_+-[]\\|");

Code:

vector<String> String::Split(bool uppercase, const char *delims)
{
	vector<String> vColl;
	char *p_tok;
	char *p = m_p;

	p_tok = strtok(p, delims);

	while (p_tok != NULL)
	{
		if (uppercase) {
			*p_tok = toupper(*p_tok);
		} else {
			*p_tok = tolower(*p_tok);
		}

		vColl.push_back(p_tok);
		p_tok = strtok(NULL, delims);  
	}

	return vColl;
}

As strange as it sounds, it's working fine now without any modification. No clue.