2 way pipe communication. cant spend from child - c

Question

I can't get this basic communication to work.
All I want to do, is send information via the child's stdout to the parents file descriptor.
I am getting a seg fault.
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#define READ 0
#define WRITE 1
int main(void){
int fdRead[2];
int pid, i, num;
FILE* output;
char mystring [100];
char c;
pid = fork();
if(pid){
FILE * read;
close(fdRead[WRITE]);
read = fdopen(fdRead[READ], "r");
fgets(mystring,100, read);
printf("parent %d",mystring );
} else {
/* child */
dup2(fdRead[WRITE], STDOUT_FILENO);
close(fdRead[READ]);
close(fdRead[WRITE]);
printf("child" );
}
exit(0);
}

Answer 1

Your code does nothing about pipe.
Code for communicating between parent and child processes using pipe looks as follows
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#define READ 0
#define WRITE 1
int main(void){
int pipefd[2];
pid_t pid;
int i, num;
if (pipe(pipefd)<0) { /* create pipe */
perror("pipe");
exit(-1);
}
char mystring [100];
char c;
pid = fork();
if(pid<0){
perror("fork");
exit(-1);
} else if (pid=1) { /* parent */
char *mystring = "message to child";
write(pipefd[WRITE],mystring,strlen(mystring);
sleep(1); /* wait for child read message */
char buf[128]; /* buffer to receive data from child */
read(pipefd[READ],buf, sizeof buf);
close(pipefd[READ]);
close(pipefd[WRITE]);
printf("Returned from child %s",buf );
return 0;
} else { /* child */
char *s="send from child: ";
char buf[128];
read(pipefd[READ],buf, sizeof buf);
write(pipefd[WRITE],s,strlen(s));
close(pipefd[READ]);
close(pipefd[WRITE]);
return 0;
}
}