C program threading

Possible duplicate of How do I start threads in plain C? Add a comment. Active Oldest Votes. Improve this answer.

Novikov Novikov 4, 2 2 gold badges 23 23 silver badges 36 36 bronze badges. OpenMP is perfect for the kind of stuff that the OP describes. Werner: That depends largely on the problem you are solving and the implementation of the algorithms. The more things that can be done completely independent from the rest, the better it lends itself to parallel execution. If ntimes is large then parallel should be faster, the bulk of the code that runs can be the same in both cases by passing off large chunks rather than individual cases.

What is ntimes? Just some value defined in some of the " ValiRossi ValiRossi 8 8 bronze badges. What would be the point of "multithreading" co-states are not threads a compute-bound process in a model where you could NEVER have true concurrency?

True state machines do not use context switches and are not "real" threads. The originator did not state what OS or platform at the time I commented. If it is a simple matter of program responsiveness, state machines may be a good solution. Certainly easier to debug. Blocking is an issue tho. Marcin Marcin 1 1 gold badge 6 6 silver badges 18 18 bronze badges. C11 threads in glibc 2. To specifically address the " automatically multithreaded" part of the OP's question: One really interesting view of how to program parallelism was designed into a language called Cilk Plus invented by MIT and now owned by Intel.

To quote Wikipedia, the idea is that "the programmer should be responsible for exposing the parallelism, identifying elements that can safely be executed in parallel; it should then be left to the run-time environment, particularly the scheduler, to decide during execution how to actually divide the work between processors.

AlcubierreDrive AlcubierreDrive 3, 2 2 gold badges 25 25 silver badges 45 45 bronze badges. You can use pthreads to perform multithreading in C. Mohd Shibli Mohd Shibli 10 10 silver badges 16 16 bronze badges. Mecki Mecki k 31 31 gold badges silver badges bronze badges. The two processes need to run for at least a minute or two to makeup for the cost of starting a new process via fork.

That said I do use fork for batch processing when each concurrent task is long lived. Output: Function 0: Function 1: Function 2: Function 3: Function 4: Function 5: Function 6: Function 7: This is a bit more representative of the real power of multithreading!

Final words Hence, unless you are multi-threading with complex computation functions, OR in case you don't need to join the threads, it will probably not be worth it due to the cost of initiating threads and also joining them. The Overflow Blog. What are the differences between process and thread? Threads are not independent of one other like processes as a result threads shares with other threads their code section, data section and OS resources like open files and signals.

But, like process, a thread has its own program counter PC , a register set, and a stack space. Why Multithreading? Threads are popular way to improve application through parallelism. For example, in a browser, multiple tabs can be different threads. MS word uses multiple threads, one thread to format the text, other thread to process inputs, etc. Threads operate faster than processes due to following reasons: 1 Thread creation is much faster.

For that, a class is needed and inside that class, operator has to be overloaded. The overloaded methods contain the program that has to be executed when the thread gets created.

Here, look at the way iin which the definition of thread object is done. An overloaded function is passed as the first parameter to the thread object and then arguments params are mentioned as the second argument. In this technique, a function pointer can be set as callable.

It can be defined as mentioned below. When this function is defined, a thread can be created using this function funct as callable as shown below. Here, the arguments or params passed to the method is provided next to the name of the function in the thread object. In addition to the above methods, a callable can also be created using a lambda expression.

It is done by passing it to the thread object for the purpose of execution. Below is the sample code snippet for the same. Any additional feedback? In the edit window, delete the existing source code and replace it with the sample code. On the Build menu, choose Build Solution. Press F5 to start the program in the debugger. Submit and view feedback for This product This page. View all page feedback. In this article.