Ignore SIGINT signal in child process

Question

I am writing a simple program in which parent and child process are alternatively printing into a file. I have managed to do this using user defined signals. Now I want to handle the SIGINT signal. Once ctrl-c is received the parent must send termination signal to child,the child should then should terminate and finally the parent should terminate.

My question is, in order to make this work properly I must catch the SIGINT signal ONLY from parent and IGNORE it from child. Is it right? If yes any hints on doing this?

Solution

Call:

signal(SIGINT, SIG_IGN);

from the child process which will make the child process ignore the SIGINT signal. From man signal:

If the disposition is set to SIG_IGN, then the signal is ignored.

Comments

[Spyros]

Ok i know the SIG_IGN action,but i want ONLY the child to ignore that and when the parent catches the signal,terminate the child.

[hmjd]

@SpyrosR, so only have the child call it?

[Spyros]

Yes.I have set two handling functions,one for parent for catching the signal and sending SITERM signal to child and one for child for ignoring the signal but i cant make it work.If for example press ctrl-c while child is "working" it does call the child handle function but it does also call the parent handle function for the SIGINT signal.