char * strpbrk

char * strpbrk(const char *__s, const char *__accept) __ATTR_PURE__

The strpbrk() function locates the first occurrence in the string s of any of the characters in the string accept.

Remember:

The strpbrk() function returns a pointer to the character in s that matches one of the characters in accept, or NULL if no such character is found. The terminating zero is not considered as a part of string: if one or both args are empty, the result will NULL.