Linux Multithreading :: C++

Hi.

I have a simple questions for Linux programmers. I am a C++ programmers, but I have no experience working with multithreaded programming in Linux. I would like to understand fork().

For example, how many processes including main process does the following code produces?

Code:

// p -> one child process

int main()
{
fork();  // p 
fork(); // p 
fork(); // p
fork(); // p

return 0;

The code above will spawn a total of five processes including main. Is that accurate?

Secondly, I would like to know let say when you spawn a process using fork() I know the child-process will execute at that very instance and all the code after it. What if you spawn one child-process after another, does the total number of processes increases exponantially?

Lastly, if you spawn a child-process inside an if statement, will the child-process execute code outside of the if statement?

Code:

int main()
{
fork();

// If child-process, then execute.
// fork() returns 0 for the child-process.

if (!forker()_
{
...
}

cout << "will the child-process execute this line?";

return 0;
}

Thanks,
Kuphryn

Okay. Thanks.

Kuphryn

Okay. Thanks.

I am taking an OS class. The book is really good, but it is a book on OS concepts and does not teach Linux implementation. The professor wants us to use the Linux lab. I have no experience working with multithreading and multiprocessing in Linux. To this day, I am not familiar with the use of fork().

I would like some advice on working with fork(), especially counting the total number of processes given a sample code like the one above. Here, I will give it another try.

-----
int main() // p
{

fork(); // p + p

if (!fork()) // p + p + p
cout << "a";

fork(); // p + p + p
fork(); // p + p + p + p

if (fork()) // p + p + p + p
fork(); // p + p + p + p + p + p

fork(); // p + p + p + p + p + p + p

return 0;
-----

I am not sure how to add the total number of processes.

Kuphryn