wcscspn function — Counts initial characters that do not match a span set
size_t wcscspn(const wchar_t* str, const wchar_t* spanset)
The wcscspn
function
returns the number of wide characters at the start of str
that are not in the wide string
spanset
. Thus, the c
in its name means complement, that is,
wcscspn
counts characters that
are in the complement of the span set.