c++ - Child process receives parent's SIGINT -

i have 1 simple program that's using qt framework. uses qprocess execute rar , compress files. in program catching sigint , doing in code when occures:

signal(sigint, &unix_handler); 

when sigint occures, check if rar process done, , if isn't wait ... problem (i think) rar process get's sigint meant program , quits before has compressed files.

is there way run rar process doesn't receive sigint when program receives ?

thanks

if generating sigint ctrl-c on unix system, signal being sent entire process group.

you need use setpgid or setsid put child process different process group not receive signals generated controlling terminal.

[edit]

be sure read rationale section of setpgid page carefully. little tricky plug of potential race conditions here.

to guarantee 100% no sigint delivered child process, need this:

#define check(x) if(!(x)) { perror(#x " failed"); abort(); /* or whatever */ } /* block sigint. */ sigset_t mask, omask; sigemptyset(&mask); sigaddset(&mask, sigint); check(sigprocmask(sig_block, &mask, &omask) == 0);  /* spawn child. */ pid_t child_pid = fork(); check(child_pid >= 0); if (child_pid == 0) {     /* child */     check(setpgid(0, 0) == 0);     execl(...);     abort(); } /* parent */ if (setpgid(child_pid, child_pid) < 0 && errno != eacces)     abort(); /* or whatever */ /* unblock sigint */ check(sigprocmask(sig_setmask, &omask, null) == 0); 

strictly speaking, every 1 of these steps necessary. have block signal in case user hits ctrl-c right after call fork. have call setpgid in child in case execl happens before parent has time anything. have call setpgid in parent in case parent runs , hits ctrl-c before child has time anything.

the sequence above clumsy, handle 100% of race conditions.