C 语言库函数使用手册
字符串函数bcmpbcopybzeromemccpymemchrmemcmpmemcpymemicmpmemmovememsetmovmemsetmemstpcpystrcatstrchrstrcmpstrcmpistrcpystrcspnstrdupstricmpstrlenstrlwrstrncatstrncmpstrncmpistrncpystrnicmpstrpbrkstrrevstrsetstrstrstrtokstrupr数学函数absacosasinatanatan2ceil