CODEWITHSUNDEEP
clinuxprocessforkpipe
Pig
Pig

Reputation: 2122

C: How to pass integer from parent to child one at a time?

HI I am trying to pass integers from 0-9 to my child process one at a time. Inside the child process I will simply print the integer. Is that even possible? Here is what I have as draft so far and it only prints the first 0.

if (pid >0){
    /*abusive parents*/
    if((close(fd[0])) == -1){
        perror("close:");}
    int k;
    for (k=0;k<10;k++){
    write(fd[1], &k, sizeof(int));
    }
    close(fd[1]);



}
else if(pid ==0){
    /*stupid child*/

    int k;
    if((close(fd[1])) == -1){
        perror("close:");} 
   read(fd[0],&k,sizeof(int));
   printf("k in child is %d\n",k);
   close(fd[0]);

}

Upvotes: 0

Views: 955

Answers (1)

Abhishek Bansal
Abhishek Bansal

Reputation: 12715

EDIT: Following works

#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>

#include <stdio.h>
#include <stdlib.h>

int main(void)
{
  int fd[2];
  pipe(fd);        
  int pid = fork();
  if (pid >0){
      /*abusive parents*/
      if((close(fd[0])) == -1){
          perror("close:");}
      int k;
      for (k=0;k<10;k++){
         write(fd[1], &k, sizeof(int));
      }
      close(fd[1]);
  }
  else if(pid ==0){
    /*stupid child*/

     int i,k;
     if((close(fd[1])) == -1){
          perror("close:");} 
     for (i=0;i<10;i++) {
        read(fd[0],&k,sizeof(int));
        printf("k in child is %d\n",k);
     }
     close(fd[0]);
  }
  return 0;
}

Output:

k in child is 0
k in child is 1
k in child is 2
k in child is 3
k in child is 4
k in child is 5
k in child is 6
k in child is 7
k in child is 8
k in child is 9

Upvotes: 2

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