| strspn | Function (ROM Call 0x278)

string.h

unsigned long strspn (const char *s1, const char *s2);

Scans a string for a segment that is a subset of a set of characters.

strspn finds the initial segment of string s1 that consists entirely of characters from string s2. Returns the length of the initial segment of s1 that consists of characters entirely from s2. If s1 contains no characters from s2, NULL is returned.