position.i4.v = str_find_character_set_c(string.i1a.r,
						 length.i4.v, direction.i4.v

	This routine will return the position of the first or last
	occurrence of any character from a requested set of characters
	in a string.  A value of FALSE is returned if no matching
	characters are found.

	string		string to search
	character_set	null terminated set of characters to search for
	length		length of string to search (a value of zero
			will result in a search up to a null terminator)
	direction	direction of search
			(STR_FIRST -> find first matching character,
			 STR_LAST -> find last matching character)
			 positive value -> find the nth occurrence of a
					   matching character from the
					   beginning of the string,
			 negative value -> find the nth occurrence of a
					   matching character from the
					   end of the string)
	[options]	option flags
			(STR_OPT_NONE -> no options selected (default),
			 STR_OPT_HANDLE_QUOTES -> don't match values in quoted

	This function returns status values as follows:

	CBS_INVARG		invalid length or direction passed
	FALSE			no matching characters found
	otherwise		position of character (starting at 1)

	This function requires the following include files:

	cnsparam_h, cbslib_h, acnet_errors_h

	Related functions:

	str_find_character_c, str_find_first_c, str_find_not_in_character_set_c,
	str_character_count_c, str_find_string_c, str_find_last_string_c,
	strstr, strstr_nocase, str_replace_char_c, str_replace_char_set_c,
	str_replace_string_c, str_get_first_c

	C/C++ usage:

	static const char	string[] = "string";
	static const char	character_set[] = "mnoqr";
	int	position;
	int	length = 0;
	int	direction = STR_FIRST;
	unsigned int	options = STR_OPT_NONE;

	position = str_find_character_set_c(string,character_set,length,