Using SIGINT and SIGTSTP to handle foreground processes a unix shell - c++

Question

I have some questions regarding the use of SIGINT and SIGTSTP in relation to managing processes in my own unix shell. But first of the code here:
void execute(vector<char *> argvv, bool x){
pid_t pid;
int status;
int error;
pid = fork();
a = pid;
argvv.push_back(NULL);
if(pid == -1){
cout << "error" << endl;
}else if(pid == 0){
error = execvp(argvv[0],argvv.data());
if(error == -1){
exit(-1);
}
// In Child Process
}else{
// If no "&", then wait for process
if(x == false){
if(wait(&status) != pid){
perror("wait()");
}
}else{
cout << "Pid des Hintergrundprozesses: " << pid << endl;
}
// in parent process
}
}
This function just receives the entered operation and parameters, forks a new process and executes it.
Now my signalhandler functions:
void signalHandlerSigInt(int signum){
cout << "Interrupt Signal (" << signum <<") received." << endl;
kill(a,SIGINT);
cout << "Killed Process: " << a << endl;
}
void signalHandlerSigTStp(int signum){
cout << "Interrupt Signal (" << signum <<") received." << endl;
kill(a,SIGTSTP);
cout << "Stop process..: " << a << endl;
}
and my main.cpp:
int main(int agc, char** argv) {
bool opBackground;
string operation;
vector<string> arguments;
vector<char *> argvv(arguments.size() + 1);
signal(SIGINT, signalHandlerSigInt);
signal(SIGTSTP, signalHandlerSigTStp);
while(true){
cout << "myshell>";
getline(cin,operation);
if(operation == "logout"){
logout();
}else{
opBackground = befehlUebersetzen(operation, &arguments);
vector<char *> argvv(arguments.size() + 1);
for(size_t i = 0; i != arguments.size(); ++i){
argvv[i] = &arguments[i][0];
}
execute(argvv, opBackground);
arguments.clear();
}
}
return 0;
}
The shell itself works fine, I now need to extend it to be able to kill the foreground process by pressing CTRL+C or stop the process with CTRL+Z.
I think I understood what a Signalhandler does, but is kill(a,SIGINT) the right way to transmit the signal SIGINT to my process? ("a" is a global variable for my forked pid, that means the last process I forked).
My problem is, when starting a process in the background and then start another process in the foreground it kills both processes when pressing CTRL+C.
Also the SIGTSTP signalhandler doesnt seem to work at all (does nothing - process just keeps running in the foreground).
Am I completely wrong with what im doing?