gistfile1.c

#include <unistd.h>
#include <stdio.h>

#include <sys/socket.h>
#include <sys/wait.h>


const int k_BufferSize = 255;

int main()
{
	int pair_soc[2];
	char buf[k_BufferSize];

	if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair_soc) == -1) {
		perror("socketpair");
		return 1;
	}

	puts("Full-duplex pipe");
	if (!fork()) {
		while (1) {
			read(pair_soc[1], &buf, k_BufferSize);
			printf("[Process 2]: <<< %s", buf);
			
			printf("[Process 2]: >>> ");
			fgets(buf, k_BufferSize, stdin);
			write(pair_soc[1], &buf, k_BufferSize);
			puts("");
		}
	} else {
		while (1) {
			printf("[Process 1]: >>> ");
			fgets(buf, k_BufferSize, stdin);
			write(pair_soc[0], buf, k_BufferSize);
			puts("");
			
			read(pair_soc[0], &buf, k_BufferSize);
			printf("[Process 1]: <<< %s", buf);
		}
		wait(NULL);
	}

	return 0;
}