The following code listing provides a trivial example of servicing annotation requests.

In order to keep the example small, safety checks such as examining API call return values are not performed.

#include <stdio.h>
#ifndef _WIN32
#include <unistd.h>    /* for getopt() */
#include <sys/signal.h>
#include <sys/param.h>
#endif
#include <sys/types.h>
#ifndef _WIN32
#include <sys/time.h>
#include <sys/socket.h>
#else
#include <WINSOCK.H>
#include <SIGNAL.H>
#endif
#include <ANNO/ANNO.h>


/* Receive function - handles the incoming
   annotation request */
int32
recvFn (
        ANNO_ConnectionId annoId,
        ANNO_RequestId requestId,
        EV_AttrValue *annoRequest
       )
{
	EV_AttrValue *annoResponse = 0;
	char *circuitName = 0;
	char *annoNodeName = 0;
	int32 seqNum;

	/* optional call */
	ANNO_getRequestInfo(requestId,
			    circuitName,
			    annoNodeName,
			    &seqNum);

	free(circuitName);
	free(annoNodeName);
	printf("annotate request, circuit=(%s),
		node=(%s), seq=(%d)\n",
		circuitName, annoNodeName, seqNum);

	/* build a response goes here */

	/* send response */
	ANNO_sendResponse(annoId, requestId,
			  annoResponse);
}


int
main( int argc, char *argv[] )
{
	ESOK_Remote remote;
	ESOK_ConnectionId conId= 0;
	ANNO_ConnectionId annoId = 0;
	int errflg = 0;
	int hflag = 0;
	char* syntax = NULL;

	extern char* optarg;
	
  
	ESOK_stackInit ();		/*manpage*/
  
	ANNO_stackInit ();		/*manpage*/

  
	ESOK_open( &remote, &conId );	/*manpage*/

					/*manpage*/
  
	ANNO_open (conId, 0, 0, *annoId);

					/*manpage*/
  
	ANNO_registerReceiveFn(
			       annoId,
			       recvFn);

	/* poll once per second until
	   the connection fails */
					/*manpage*/
  
	while (ESOK_process(1000) >= 0);

	
  
	ANNO_close(annoId);		/*manpage*/
  
	ANNO_stackReset();		/*manpage*/
  
	ESOK_close( cid );		/*manpage*/
  
	ESOK_stackReset();		/*manpage*/
"../refs/c/esok_stackReset.htm"
	exit (0);
}