Question

I got some weird output:

Read 0 bytes: P
?\?  

from my code:

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

char phrase[0] = "stuff this in your pipe and smoke it";
int main(int argc, char* argv[]) {
    int fd[2], bytesRead;
    char message[100];
    int pid;
    pid = fork();
    pipe(fd);
    if (pid == 0) {
        close(fd[0]);
        write(fd[1], phrase, strlen(phrase) + 1);
        close(fd[1]);
    }else {
        close(fd[1]);
        bytesRead = read(fd[0], message, 100);
        printf("Read %d bytes: %s\n", bytesRead, message);
        close(fd[0]);

    }
}

I don’t know where I goes wrong, any idea?

Answer 1

pid = fork();
pipe(fd);

This example works when child processes inherit descriptors from the parent. You’ll want to call pipe before you fork.