展讯 如何将gb2312的格式编码转ucs2

unsigned long  gb2312_to_ucs2(              // return the UCS2 count
    const unsigned  char *  gb2312,         // the pointer that contain the gb2312 string
    unsigned int            gb2312_size,    // the bytes count that the gb2312 string length
    unsigned short       *  ucs2,           // the buffer that store the converted ucs2
    unsigned long           max_ucs2)

GUI_GBToWstr

ucs2的格式编码转gb2312呢?