mbtowc
chrlen = mbtowc(&c, *p, 4);
int mbtowc(wchar_t *, const char*, size_t);
if ((len = mbtowc(&wc, sp, MB_CUR_MAX)) == -1) {
(void)mbtowc(NULL, NULL, MB_CUR_MAX);
int mbtowc(wchar_t * __restrict, const char * __restrict, size_t);
__mbstate_t mbtowc;
XLOCALE_CTYPE(locale)->mbtowc = initial;
&(XLOCALE_CTYPE(locale)->mbtowc));
memset(&l->mbtowc, 0, sizeof(l->mbtowc));
ATF_REQUIRE(mbtowc(&wc, buf, 1) == -1);
ATF_REQUIRE(mbtowc(NULL, NULL, 0) == 0);
ATF_REQUIRE(mbtowc(&wc, buf, 2) == 2);
ATF_REQUIRE(mbtowc(NULL, NULL, 0) == 0);
ATF_REQUIRE(mbtowc(&wc, buf, 1) == 0);
ATF_REQUIRE(mbtowc(&wc, buf, 1) == 1);
ATF_REQUIRE(mbtowc(&wc, buf, 0) == -1);
ATF_REQUIRE(mbtowc(NULL, NULL, 0) == 0);
ATF_REQUIRE(mbtowc(&wc, buf, 1) == 0);
ATF_REQUIRE(mbtowc(&wc, buf, 1) == 1);
ATF_REQUIRE(mbtowc(&wc, buf, 0) == -1);
ATF_REQUIRE(mbtowc(NULL, NULL, 0) == 0);
res = mbtowc(wc, c, mb_cur_max);