bind.c


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#include <sys/socket.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <arpa/inet.h>
#include <unistd.h>

static void fail(const char *err) {
	perror(err);
	exit(1);
}

int main(int argc, char **argv) {
	unsigned short int port;
	int sockfd;
	struct sockaddr_in addr;
	struct in_addr sa;

	if (argc < 2) {
		printf("Usage: %s port\n", argv[0]);
		return -1;
	}
	port = atoi(argv[1]);
	printf("Port: %hu\n", port);

	sockfd = socket(AF_INET, SOCK_STREAM, 0);
	if (sockfd < 0) fail("socket");

	memset(&addr, 0, sizeof addr);
	addr.sin_family = AF_INET;
	addr.sin_port = htons(port);
	sa.s_addr = htonl(INADDR_LOOPBACK);
	addr.sin_addr = sa;
	printf("sockfd = %i\naddr   = %p\nsizeof addr = %zi\n", sockfd,
		(struct sockaddr *)&addr, sizeof addr);
	if (bind(sockfd, (struct sockaddr *)&addr, sizeof addr) < 0) fail("bind");

	if (listen(sockfd, 10) < 0) fail("listen");

	if (close(sockfd) < 0) fail("close");
	printf("Success!\n");
	return 0;
}