How do I start threads in plain C?

I have used fork() in C to start another process. How do I start a new thread?

Solution 1:

Since you mentioned fork() I assume you're on a Unix-like system, in which case POSIX threads (usually referred to as pthreads) are what you want to use.

Specifically, pthread_create() is the function you need to create a new thread. Its arguments are:

int  pthread_create(pthread_t  *  thread, pthread_attr_t * attr, void *
   (*start_routine)(void *), void * arg);

The first argument is the returned pointer to the thread id. The second argument is the thread arguments, which can be NULL unless you want to start the thread with a specific priority. The third argument is the function executed by the thread. The fourth argument is the single argument passed to the thread function when it is executed.

Solution 2:

AFAIK, ANSI C doesn't define threading, but there are various libraries available.

If you are running on Windows, link to msvcrt and use _beginthread or _beginthreadex.

If you are running on other platforms, check out the pthreads library (I'm sure there are others as well).