void *memchr(const void *s, int c, size_t n);
IEEE Std 1003.1-2017
memchr() function shall locate the first occurrence of c (converted to an unsigned char) in the initial
n bytes (each interpreted as unsigned char) pointed to by s.
Implementations shall behave as if they read the memory byte by byte from the beginning of the bytes pointed to by s and stop at the first occurrence of c (if it is found in the initial n bytes).
memchr() function shall return a pointer to the located byte, or a
null pointer if the byte is not found.
No errors are defined.