Socket Handles to C

socket plugin using own data structure for socket handles,

it includes different kind of internal information, including OS-specific socket handle.

 
typedef struct
{
  int   sessionID;
  int   socketType;  /* 0 = TCP, 1 = UDP */
  void  *privateSocketPtr;
}  SQSocket, *SocketPtr;

extracting the OS-specific handle could be problematic, since it is in

that opaque void  *privateSocketPtr; field.

Then:

sqUnixSocket.c

typedef struct privateSocketStruct
{
  int s;            /* Unix socket */
  int connSema;            /* connection io notification semaphore */
  int readSema;            /* read io notification semaphore */
  int writeSema;        /* write io notification semaphore */
  int sockState;        /* connection + data state */
  int sockError;        /* errno after socket error */
  union sockaddr_any peer;    /* default send/recv address for UDP */
  socklen_t peerSize;        /* dynamic sizeof(peer) */
  union sockaddr_any sender;    /* sender address for last UDP receive */
  socklen_t senderSize;        /* dynamic sizeof(sender) */
  int multiListen;        /* whether to listen for multiple connections */
  int acceptedSock;        /* a connection that has been accepted */
} privateSocketStruct;

so, to extract OS-level socked handle *on unix*, you have to

handle = ( (privateSocketStruct*) sqsocket.privateSocketPtr) -> s.

where sqsocket is SQSocket.

there's even macros for that:

/*** Accessors for private socket members from a Squeak socket pointer ***/

#define _PSP(S)        (((S)->privateSocketPtr))
#define PSP(S)        ((privateSocketStruct *)((S)->privateSocketPtr))

#define SOCKET(S)        (PSP(S)->s)
#define SOCKETSTATE(S)        (PSP(S)->sockState)
#define SOCKETERROR(S)        (PSP(S)->sockError)
#define SOCKETPEER(S)        (PSP(S)->peer)
#define SOCKETPEERSIZE(S)    (PSP(S)->peerSize)