C++ Timed Process - c++

Question

I'm trying to set up some test software for code that is already written (that I cannot change). The issue I'm having is that it is getting hung up on certain calls, so I want to try to implement something that will kill the process if it does not complete in x seconds.
The two methods I've tried to solve this problem were to use fork or pthread, both haven't worked for me so far though. I'm not sure why pthread didn't work, I'm assuming it's because the static call I used to set up the thread had some issues with the memory needed to run the function I was calling (I continually got a segfault while the function I was testing was running). Fork worked initially, but on the second time I would fork a process, it wouldn't be able to check to see if the child had finished or not.
In terms of semi-pseudo code, this is what I've written
test_runner()
{
bool result;
testClass* myTestClass = new testClass();
pid_t pID = fork();
if(pID == 0) //Child
{
myTestClass->test_function(); //function in question being tested
}
else if(pID > 0) //Parent
{
int status;
sleep(5);
if(waitpid(0,&status,WNOHANG) == 0)
{
kill(pID,SIGKILL); //If child hasn't finished, kill process and fail test
result = false;
}
else
result = true;
}
}
This method worked for the initial test, but then when I would go to test a second function, the if(waitpid(0,&status,WNOHANG) == 0) would return that the child had finished, even when it had not.
The pthread method looked along these lines
bool result;
test_runner()
{
long thread = 1;
pthread_t* thread_handle = (pthread_t*) malloc (sizeof(pthread_t));
pthread_create(&thread_handle[thread], NULL, &funcTest, (void *)&thread); //Begin class that tests function in question
sleep(10);
if(pthread_cancel(thread_handle[thread] == 0))
//Child process got stuck, deal with accordingly
else
//Child process did not get stuck, deal with accordingly
}
static void* funcTest(void*)
{
result = false;
testClass* myTestClass = new testClass();
result = myTestClass->test_function();
}
Obviously there is a little more going on than what I've shown, I just wanted to put the general idea down. I guess what I'm looking for is if there is a better way to go about handling a problem like this, or maybe if someone sees any blatant issues with what I'm trying to do (I'm relatively new to C++). Like I mentioned, I'm not allowed to go into the code that I'm setting up the test software for, which prevents me from putting signal handlers in the function I'm testing. I can only call the function, and then deal with it from there.

Answer 1

If c++11 is legit you could utilize future with wait_for for this purpose.
For example (live demo):
std::future<int> future = std::async(std::launch::async, [](){
std::this_thread::sleep_for(std::chrono::seconds(3));
return 8;
});
std::future_status status = future.wait_for(std::chrono::seconds(5));
if (status == std::future_status::timeout) {
std::cout << "Timeout" <<endl ;
} else{
cout << "Success" <<endl ;
} // will print Success
std::future<int> future2 = std::async(std::launch::async, [](){
std::this_thread::sleep_for(std::chrono::seconds(3));
return 8;
});
std::future_status status2 = future2.wait_for(std::chrono::seconds(1));
if (status2 == std::future_status::timeout) {
std::cout << "Timeout" <<endl ;
} else{
cout << "Success" <<endl ;
} // will print Timeout
Another thing:
As per the documentation using waitpid with 0 :
meaning wait for any child process whose process group ID is equal to
that of the calling process.
Avoid using pthread_cancel it's probably not a good idea.