pipes

Work in Progress

Concept

basic synchronous message passing mechanism
acts as an anonymous file
producer-consumer relationship
circular buffer with implicit syncrhonization

pipes provide two file descriptors, that refer to the same buffer, but have different read/write permissions

half duplex

int p[2]; // 2 file descriptors
char str[] = "Hello this is the parent.";

if(pipe(p) < 0) 
		perror("Error: ");

// send a message from parent to child
if(fork() != 0) {
		close(p[0]); // close the read end
		write(p[1], str, strlen(str));
		close(p[1]);
		wait(NULL); // wait for child
} else {
		char buffer[128];

		close(p[1]); // close the write end
		read(p[0], buffer, 127);
		printf("Child got the message \"%s\"\n", buffer);
		close(p[0]);
}