Unix/Linux进程间通信——Socket

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

int main(int argc, char *argv[])
{
	int sd, client, bytes_read;
	struct sockaddr_in server;
	char buf[512];

	// 1. Open a socket
	sd = socket(PF_INET, SOCK_STREAM, 0);
	if (sd < 0) {
		puts("Could not create socket");
		return -1;
	}

	server.sin_family = AF_INET;
	server.sin_addr.s_addr = inet_addr("127.0.0.1");
	server.sin_port = htons(8000);

	// 2. Bind to a address(and port)
	if (bind(sd, (struct sockaddr *)&server, sizeof(server)) < 0) {
		puts("Bind failed");
		close(sd);
		return -1;
	}
	puts("Bind done");

	// 3. Listen for incoming connections
	listen(sd, 8);

	while (1) {
		// 4. Accept connections
		puts("Waiting for incoming connections...");
		client = accept(sd, NULL, NULL);
		if (client < 0) {
			puts("Accept failed");
		}
		puts("Connection accepted");

		// 5. Read/Write
		bytes_read = recv(client, buf, sizeof(buf), 0);
		if (bytes_read > 0) {
			puts(buf);
		}

		close(client);
	}
	close(sd);

	return 0;
}

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

int main(int argc, char *argv[])
{
	struct sockaddr_in server;
	int sd;
	char *message;

	// 1. Create a socket
	sd = socket(PF_INET, SOCK_STREAM, 0);
	if (sd < 0) {
		printf("Could not create socket");
		return -1;
	}

	server.sin_addr.s_addr = inet_addr("127.0.0.1");
	server.sin_family = AF_INET;
	server.sin_port = htons(8000);

	// 2. Connect to remote server
	if (connect(sd, (struct sockaddr *)&server, sizeof(server)) < 0) {
		puts("Connect error");
		close(sd);
		return -1;
	}
	puts("Connected");

	// 3. Send some data
	message = "Hello World!";
	if (send(sd, message, strlen(message)+1, 0) < 0) {
		puts("Send failed");
		close(sd);
		return -1;
	}
	puts("Send done");

	close(sd);

	return 0;
}