xboard chess gui doesn't send second user move

Question

I am trying to make a chess engine for xboard. After the first move made by user, my chess engine replies, and then xboard doesn't send the next move made by the user.

I recorded whatever xboard sends to my engine. Here's a code sample where my engine replies e2e4 with move e7e6:

#include <iostream>
#include <fstream>
#include <unistd.h>

std::ofstream f("xboardtoeng.txt");
std::ofstream f2("engtoxboard.txt");

int main(int argc, char** argv){  

    while (true){
        std::string s;
        std::cin>>s;
        f<<s<<std::endl;
        if (s=="protover"){
            std::cout<<"feature done=1"<<std::endl;
            f2<<"feature done=1"<<std::endl;
        }else if (s=="e2e4"){
            usleep(100000);
            std::cout<<"move e7e6"<<std::endl;
            f2<<"move e7e6"<<std::endl;
        }
    }
    f.close();
}

After compiling, I ran xboard -fcp $PWD/a.out. Then, I made e2e4 move as user in the GUI. After my engine gives its reply, I made another move (say, e4e5). Here's what I got in xboardtoeng.txt:

xboard
protover 2
accepted usermove
accepted myname
accepted done
new
random
level 40 5 0
post
hard
time 30000
otim 30000
usermove e2e4

Here, xboard did send the first move to my engine. However, the next user move isn't sent. Any idea where I did wrong?

I use xboard version 4.8.0

Answer 1

I have the same problem, it is because Xboard send SIGINT and SIGTERM signal. Adding code signal(SIGINT, SIG_IGN) solve my problem.

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