TESTCASE( memchr( abcde, 'c', 5 ) == &abcde[2] );
TESTCASE( memchr( abcde, 'a', 1 ) == &abcde[0] );
TESTCASE( memchr( abcde, 'a', 0 ) == NULL );
TESTCASE( memchr( abcde, 'c', 5 ) == &abcde[2] );
TESTCASE( memchr( abcde, 'a', 1 ) == &abcde[0] );
TESTCASE( memchr( abcde, 'a', 0 ) == NULL );