wcscspn
size_t wcscspn(const wchar_t *, const wchar_t *);
i = wcscspn(el->el_line.cursor, match_chars);
ATF_TC(wcscspn);
ATF_TC_HEAD(wcscspn, tc)
ATF_TC_BODY(wcscspn, tc)
ATF_CHECK_EQ(wcscspn(L"abcdefghijklmnop", L""), 16);
ATF_CHECK_EQ(wcscspn(L"abcdefghijklmnop", L"a"), 0);
ATF_CHECK_EQ(wcscspn(L"abcdefghijklmnop", L"b"), 1);
ATF_CHECK_EQ(wcscspn(L"abcdefghijklmnop", L"cd"), 2);
ATF_CHECK_EQ(wcscspn(L"abcdefghijklmnop", L"qrstuvwxyz"), 16);
ATF_TP_ADD_TC(tp, wcscspn);