IN_ADDR - NtDoc

#ifndef _NTRTL_H
//
// IPv4/6 conversion
//
#ifndef s_addr

//
// IPv4 Internet address
// This is an 'on-wire' format structure.
//
typedef struct in_addr
{
    union
    {
        struct { UCHAR s_b1, s_b2, s_b3, s_b4; } S_un_b;
        struct { USHORT s_w1, s_w2; } S_un_w;
        ULONG S_addr;
    } S_un;
#define s_addr  S_un.S_addr /* can be used for most tcp & ip code */
#define s_host  S_un.S_un_b.s_b2    // host on imp
#define s_net   S_un.S_un_b.s_b1    // network
#define s_imp   S_un.S_un_w.s_w2    // imp
#define s_impno S_un.S_un_b.s_b4    // imp #
#define s_lh    S_un.S_un_b.s_b3    // logical host
} IN_ADDR, * PIN_ADDR, FAR* LPIN_ADDR;

#endif
#endif
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