memchr - scan memory for a character
void *memchr(const void *s, int c, size_t n);
The memchr() function scans the first n bytes of the memory area
pointed to by s for the character c. The first byte to match
c (interpreted as an unsigned character) stops the operation.
The memchr() function returns a pointer to the matching byte or NULL if
the character does not occur in the given memory area.
SVID 3, BSD 4.3, ISO 9899