wcstok.c\string\src - musl - musl - an implementation of the standard library for Linux-based systems

#include <wchar.h>
wchar_t *wcstok(wchar_t *restrict s, const wchar_t *restrict sep, wchar_t **restrict p)
{
	if (!s && !(s = *p)) return NULL;
	s += wcsspn(s, sep);
	if (!*s) return *p = 0;
	*p = s + wcscspn(s, sep);
	if (**p) *(*p)++ = 0;
	else *p = 0;
	return s;
}