socket() returns "Invalid argument". Why? (UNPv1)

[Fernando Gont <fernando@gont.com.ar>]

Hi!

I compiled this simple TCP daytime client, expecting to get a
EPFNOSUPPORT error.


#include	"unp.h"

int
main(int argc, char **argv)
{
	int					sockfd, n;
	char				recvline[MAXLINE + 1];
	struct sockaddr_in	servaddr;

	if (argc != 2)
		err_quit("usage: a.out <IPaddress>");

	if ( (sockfd = socket(9999, SOCK_STREAM, 0)) < 0){
		printf("errno: %d\n", errno);
		err_sys("socket error");
	}

	bzero(&servaddr, sizeof(servaddr));
	servaddr.sin_family = AF_INET;
	servaddr.sin_port   = htons(13);	/* daytime server */
	if (inet_pton(AF_INET, argv[1], &servaddr.sin_addr) <= 0)
		err_quit("inet_pton error for %s", argv[1]);

	if (connect(sockfd, (SA *) &servaddr, sizeof(servaddr)) < 0)
		err_sys("connect error");

	while ( (n = read(sockfd, recvline, MAXLINE)) > 0) {
		recvline[n] = 0;	/* null terminate */
		if (fputs(recvline, stdout) == EOF)
			err_sys("fputs error");
	}
	if (n < 0)
		err_sys("read error");

	exit(0);
}


But after compiling and running this program, I see that errno gets the 
value 22, and having a look at the header files, I see:

#define	EINVAL		22	/* Invalid argument */
#define	EPFNOSUPPORT	96	/* Protocol family not supported */
#define	EAFNOSUPPORT	97	/* Address family not supported by protocol */

My question is: if I don't get a EPFNOSUPPORT error for this example, when 
would I get it?

Greetings, Fernando (fernando@gont.com.ar)

"I believe it is a Human impossibility to obtain complete peace of mind
  in this dimension. There's too much suffering and pain -- particularly
  for children."  -Dolores O'Riordan


-
: send the line "unsubscribe linux-net" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html