btowc
wint_t btowc(int);
*(cp = buf) = (wchar_t)btowc(GETARG(int));
ATF_REQUIRE(btowc(EOF) == WEOF);
ATF_REQUIRE(btowc(i) == (wchar_t)i && i == (int)wctob(i));
ATF_REQUIRE(btowc('A') == L'A' && wctob(L'A') == 'A');
ATF_REQUIRE(btowc(0xa3) == WEOF && wctob(0xa3c1) == EOF);
y->bytetab[i] = (btowc(i) != WEOF) ? i : 0;
eols = zero_ended ? btowc('\0') : btowc('\n');
sort_opts_vals.field_sep = btowc(optarg[0]);