pragma pack(n)用法

2012-11-01 09:15:40 · 作者: · 浏览: 396
  表示n字节对齐,比如n=1
  
  typedef struct
  
  {
  
  short Type;//2字节
  
  size_t Size;//4字节
  
  short Reserved1;//2字节
  
  short Reserved2;//2字节
  
  size_t OffBits;//4字节
  
  } BMP_FILE_HEADER;
  
  结果:    sizeof(BMP_FILE_HEADER)=16
  
  #pragma pack(1)
  
  typedef struct
  
  {
  
  short Type;
  
  size_t Size;
  
  short Reserved1;
  
  short Reserved2;
  
  size_t OffBits;
  
  } BMP_FILE_HEADER;
  
  pragma pack();
  
  结果:    sizeof(BMP_FILE_HEADER)=14