#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <errno.h>
#include <netinet/in.h>   
#include <netdb.h>       
#include <fcntl.h>
#include <sys/ipc.h>
#include <sys/stat.h>
#include <unistd.h>
#include <sys/sem.h>
#include <sys/un.h>     

main ()
{
	struct protoent*   protocol;
	int result;

	if ( ! (protocol = getprotobyname("ip")) ) {
	   fprintf(stderr,"getprotobyname fails\n");
	   exit(1);
	}
	endprotoent();
	printf("protocol returned by getprotobyname is %d\n", 
		protocol->p_proto);
	result = socket((int)AF_UNIX, SOCK_STREAM, protocol->p_proto);
	if (result == -1) {
      perror("socket initialization failed");
      exit(0);
	}
	printf("socket returned successfully with descriptor %d\n",
		result);
	exit(0);
}




.