The following code will create a pipe for each child, fork the process as many times as it is needed and send from the parent to each child a random int value, finally the children will read the value and terminate.
#include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <time.h> int main(int argc, char *argv[]) { int count = 3; int fd[count][2]; int pid[count]; srand(time(NULL)); // create pipe descriptors for (int i = 0; i < count; i++) { pipe(fd[i]); // fork() returns 0 for child process, child-pid for parent process. pid[i] = fork(); if (pid[i] != 0) { // parent: writing only, so close read-descriptor. close(fd[i][0]); // send the value on the write-descriptor. int r = rand(); write(fd[i][1], &r, sizeof(r)); printf("Parent(%d) send value: %d\n", getpid(), r); // close the write descriptor close(fd[i][1]); } else { // child: reading only, so close the write-descriptor close(fd[i][1]); // now read the data (will block) int id; read(fd[i][0], &id, sizeof(id)); printf("%d Child(%d) received value: %d\n", i, getpid(), id); // close the read-descriptor close(fd[i][0]); //TODO cleanup fd that are not needed break; } } return 0; }
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