example/posix/threads-simple_usage.cpp

Shows basic usage of the FRI-OS wrapped POSIX threads

//LDFLAGS = -lpthread

#include <iostream>
#include <cstdlib>

#include <frios/posix.hpp>

// Structure storing input data and place for the result of the computation
struct computation
{
    int argument;
    unsigned long long result;
};

// naive implementation of the fibonacci function
unsigned long long fib(int n)
{
    if(n < 2) return 1;
    else return fib(n-2) + fib(n-1);
}

// the thread's main function
void* calc_fib(void* raw_ptr)
{
    // cast the raw pointer to the proper type
    computation* c = static_cast<computation*>(raw_ptr);
    // calculate the value of the fibonacci function
    // for the specified argument and store it into result
    c->result = fib(c->argument);

    return nullptr;
}

int main(int argc, const char* argv[])
{
    // get the argument
    int arg = (argc>1)?std::atoi(argv[1]):42;
    if(arg <= 0) arg = 42;
    // initialize the data for the computation
    // NOTE that the object must exist during the whole
    // lifetime of the thread
    computation comp = {arg, 0};
    // start the worker thread
    frios::posix::thread worker(calc_fib, &comp);
    // wait for the thread to finish
    worker.wait_for();
    // print the result
    std::cout << "fib(" << comp.argument << ") = " << comp.result << std::endl;

    return 0;
}