3_client.c

#include <sys/socket.h>
#include <sys/un.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/uio.h>
#include <unistd.h>
#include <netdb.h>
#include <arpa/inet.h>

int
main(int argc, const char **argv)
{
	int sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
	if (sock == -1) {
		printf("error = %s\n", strerror(errno));
		return -1;
	}
	struct addrinfo *addr;
	struct addrinfo filter;
	memset(&filter, 0, sizeof(filter));
	filter.ai_family = AF_INET;
	filter.ai_socktype = SOCK_STREAM;
	int rc = getaddrinfo(argv[1], argv[2], &filter, &addr);
	if (rc != 0) {
		printf("addrinfo error = %s\n", gai_strerror(rc));
		close(sock);
		return -1;
	}
	if (addr == NULL) {
		printf("not found a server\n");
		freeaddrinfo(addr);
		close(sock);
		return -1;
	}
	rc = connect(sock, addr->ai_addr, addr->ai_addrlen);
	freeaddrinfo(addr);
	if (rc != 0) {
		printf("connect error = %s\n", strerror(errno));
		close(sock);
		return -1;
	}
	int number;
	while (scanf("%d", &number) > 0) {
		if (send(sock, &number, sizeof(number), 0) == -1) {
			printf("error = %s\n", strerror(errno));
			continue;
		}
		printf("Sent %d\n", number);
		number = 0;
		int rc = recv(sock, &number, sizeof(number), 0);
		if (rc == 0) {
			printf("Closed connection\n");
			break;
		}
		if (rc == -1)
			printf("error = %s\n", strerror(errno));
		else
			printf("Received %d\n", number);
	}
	close(sock);
	return 0;
}