-// ²éÕÒÔڼϺÏsetËùָ֨µÄÄÇЩ×ַûÔÚstrµĿªʼԦ³öÏֵÄ×î´ó¸öÊý
-// Èçstr="13134abcde", set="1234567890", wcsspn(str,set)==5
-// Èçstr="abcde", set="1234567890", wcsspn(str,set)==0
+/*
+ * wcsspn: compute the maxinum initial segment of the wide-char str which consists entirely of wide-char codes from the set.
+ * returnt he length of the initial substring of str
+ * examples:
+ * str="13134abcde", set="1234567890", wcsspn(str,set)==5
+ * str="abcde", set="1234567890", wcsspn(str,set)==0
+ */