fork() // parent & child communication

sudif · 05-01-2007, 11:14 AM

i need to write a program that receives data from the child process and execute on it in the parent then the parent waits for the child to send the data again.

can i do it using fork wait and pipe and how???

Centinul · 05-01-2007, 11:27 AM

I believe the short answer is: yes you can communicate between the parent and child process using a pipe.

The long answer is: I don't know how to do it off the top of my head. Spend some time googling and I'm sure you'll find it. I found it via Google when I was researching how to do it.

HTH

sudif · 05-01-2007, 12:05 PM

couldn't find exactly what i need

Whyte · 05-01-2007, 12:15 PM

Code:

int p[2];
pipe(p); // also check if it returns <0 (error)
// p[0] should now be open for reading
// p[1] for writing

Then do a fork(), and (you MUST) close() the Read descriptor in one process, and the Write descriptor in the other process. Then, whatever you write() into p[1], you will read from p[0].

man 2 pipe for details. man 3 mkfifo for another approach.

Kristofer · 05-01-2007, 01:30 PM

http://www.ecst.csuchico.edu/~beej/guide/ipc/pipes.html

Take a look at "fork() and pipe()--you have the power!"

/Kristofer

bigearsbilly · 05-02-2007, 03:11 AM

you should explain precisely what you are trying to do, not how you want it done.