Signals and threads

Nov 24, 2006 2 Replies
S

Hi



I have a problem using sigaction function in pthread library. I have 2 thread each one registering



in threadA act1.sa_handler=func1; if(sigaction(SIGUSR1,&act1,NULL)) printf("\nSigaction failed! in th1 !!\n");



in threadB act1.sa_handler=func2; if(sigaction(SIGUSR1,&act2,NULL)) printf("\nSigaction failed! in th2 !!\n");



but when i send signal SIGUSR1 to threadA , threadA receives the signal but the handler func2 is getting called,


Please let me know is there any way to solve this problem? thanks in advance thomas



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M

See the thread "Communication between threads of same PIDs" in this forum. Does that help ?

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S

thanks for the response, It does not solve the problem.

In the pthread_library clone call is used , In the man page of clone its given that if CLONE_SIGHAND is not defined, the signal handlers will not be shared between threads. I recompiled the pthread library with out CLONE_SIGHAND .

I linked the program with the new library , It has been ok in the do_fork call in the pthread funciton, A new struct of task_struct->sig is allocated. Also i have seen that the sigaction function call in the thread modifies and install a new handler in this already allocated task_struct->sig structure. Inspite of all this the last sig handler function is getting called when i send the signal to the first thread. Any clue???

thanks thomas

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