The structure body contains bit segments, and its data memory distribution

struct _packer_data { unsigned char isdll:1; Whether it is a DLL unsigned char config:3; Set unsigned char oldoep:4; Program Entry point int nSize; Bit and non-segment data can coexist }; Structure Expansion: ?1<------1bit------>|<------3bit------->|<------4bit------>|<-------32bit--------> | isdll Config Oldoep nSize G_stcpackdata.isdll = 1; 1 g_stcpackdata.config = 5; 101 (if more than 3 bits, take only 3 bits lower) G_stcpackdata.oldoep = 9; 1001 g_stcpackdata.nsize = 0xFFFFFFFF g_stcpackdata structure variables in-memory data are arranged in: 9B the FF FF FF FF //According to VS default 8 byte aligned|---> 1001 1011 (Right-to-left arrangement of bit data) oldoep+config+isdll

The structure body contains bit segments, and its data memory distribution