请问VC高手？(10分)

请问在m_time的数据类型time_t是几个字节的?
typedef struct tagRCV_REPORT_STRUCTExV3
{
WORD m_cbSize;
time_t m_time;
WORD m_wMarket;
char m_szLabel[STKLABEL_LEN];
char m_szName[STKNAME_LEN];
float m_fLastClose;
float m_fOpen;
float m_fHigh;
float m_fLow;
float m_fNewPrice;
float m_fVolume;
float m_fAmount;
float m_fBuyPrice[3]; float m_fBuyVolume[3]; float m_fSellPrice[3]; float m_fSellVolume[3];
float m_fBuyPrice4; float m_fBuyVolume4; float m_fSellPrice4; float m_fSellVolume4; float m_fBuyPrice5;
float m_fBuyVolume5;
float m_fSellPrice5;
float m_fSellVolume5;
} RCV_REPORT_STRUCTExV3;

没有定义谁都不知道，sizeof()搞定