Re: Sockets - Gpc

1 Dec 1997


      Hello, Matthew!  Hi, everybody!
According to RHS Linux User:
...
I was trying to open a socket, but the problem I kept running into was
that connect wants a sockaddr struct, and in C you just casted it...
(struct sockaddr *)&address but, I don't think that that is possible in
pascal, [...]
Since you cannot simply #include a C header file in a Pascal
program you have to define the type by yourself:
Const
      AF_UNSPEC     = 0;
      AF_UNIX       = 1;       (* Unix domain sockets          *)
      AF_INET       = 2;       (* Internet IP Protocol         *)
      AF_AX25       = 3;       (* Amateur Radio AX.25          *)
      AF_IPX        = 4;       (* Novell IPX                   *)
      AF_APPLETALK  = 5;       (* Appletalk DDP                *)
      AF_NETROM     = 6;       (* Amateur radio NetROM         *)
      AF_BRIDGE     = 7;       (* Multiprotocol bridge         *)
      AF_AAL5       = 8;       (* Reserved for Werner's ATM    *)
      AF_X25        = 9;       (* Reserved for X.25 project    *)
    (*$ifdef LINUX_2_1_X *)
      AF_INET6      = 10;      (* IP version 6                 *)
    (*$endif *)
      AF_MAX        = 12;      (* For now.. *)
Type
      SockAddrPtr = ^SockAddr;
      SockAddr = record
        case family: ShortCard of
          AF_UNSPEC: ( data: packed array [ 0..13 ] of Char );
          AF_INET:   ( port: ShortWord;
                       address: array [ 1..4 ] of Byte );
      end (* SockAddr *);
Having this you can declare a variable `Address' of type `SockAddr',
so `@Address' will have the correct type - no need to cast.  However,
`SockAddrPtr ( @Address )' is the exact analogon of your C fragment
above.
Hope this helps,
Peter
Dipl.-Phys. Peter Gerwinski, Essen, Germany, free physicist and programmer
peter.gerwinski@uni-essen.de - http://home.pages.de/~peter.gerwinski/ [971005]
 maintainer GNU Pascal [971001] - http://home.pages.de/~gnu-pascal/ [971005]