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I'm writing a winsock application, but i have problems with some winsock structures where unions are used.

Particulary with this one ( this is the C definition from whinsock2.h):

struct in_addr {

        union {

                struct { u_char s_b1,s_b2,s_b3,s_b4; } S_un_b;

                struct { u_short s_w1,s_w2; } S_un_w;

                u_long 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 */

};



I ended with following fasm definition. It works fine, but i know it isn't quite correct 



struc in_addr

{

  .S_un dd 0

  virtual at .S_un

  	.S_un_b _S_un_b

  end virtual

  virtual at .S_un

  	.S_un_w _S_un_w

  end virtual

  virtual at .S_un

	.S_addr dd 0

  end virtual

  

  .s_addr equ .S_addr ;#define s_addr  S_un.S_addr

                               ; /* can be used for most tcp & ip code */

  .s_host equ .S_un_b.s_b2 ;#define s_host  S_un.S_un_b.s_b2

                               ; /* host on imp */

  .s_net   equ .S_un_b.s_b1;#define s_net   S_un.S_un_b.s_b1

                                ;/* network */

  .s_imp   equ .S_un_w.s_w2;#define s_imp   S_un.S_un_w.s_w2

                                ;/* imp */

  .s_impno equ .S_un_b.s_b4;#define s_impno S_un.S_un_b.s_b4

                                ;/* imp # */

  .s_lh    equ .S_un_b.s_b3;#define s_lh    S_un.S_un_b.s_b3

                                ;/* logical host */

}



struc _S_un_b

{

  .s_b1 db 0

  .s_b2 db 0

  .s_b3 db 0

  .s_b4 db 0	

}

struc _S_un_w

{

  .s_w1 dw 0

  .s_w2 dw 0

}

Any ideas how to correctly define in_addr in a way that .S_un_b, .S_un_w and .S_addr members are accesible thru .S_un?
Here is attached a sample test application

Posted on 2002-12-01 07:27:54 by rdo