The section of code that is meant to run in parallel is marked accordingly, with a compiler directive that will cause the threads to form before the section is executed. Each thread has an "id" attached to it which can be obtained using a function (called codice_1). The thread id is an integer, and the primary thread has an id of "0". After the execution of the parallelized code, the threads "join" back into the primary thread, which continues onward to the end of the program.