CODEWITHSUNDEEP
c++linuxsignalsfile-descriptor
denh
denh

Reputation: 189

How to invoke a process sleeping on poll function by another thread in the same process with signal without killing it?

I want to manually wake up (by another thread in the same process) a thread sleeping on poll() function waiting for any input data available. Looks like I found a possible solution by sending signals, but I don't have any experience with them really. On this page I found a signal called SIGPOLL with codes like POLL_IN, POLL_MSG, but when I call it, the whole process is killed. How to send this signal without killing the whole process ?

Upvotes: 0

Views: 427

Answers (1)

denh
denh

Reputation: 189

I used pipe() to solve this problem.

void a(int invokefd){
     ...
     write(invokefd, "c", 1);
     ...
}

void b(int invokefd){
     vector<pollfd> readfds;
     ...
     pollfd invfd;
     invfd.fd = invokefd;
     invfd.events = POLLIN;
     invfd.revents = 0;
     readfds.push_back(invfd);
     ...
     poll(&readfds[0], readfds.size(), -1);
     ...
}

void main(){
     ...
     int invokedfs[2];
     pipe(invokefds);
     thread aTh(a, invokefds[1]);
     thread bTh(b, invokefds[0]);
     ...
}

Upvotes: 1

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