Search code examples
cpthreadsmutexstatic-initialization

Static pthreads mutex initialization

Using pthreads, how would one, in C, initialize a static array of mutexes?

For a single static mutex, it seems I can use PTHREAD_MUTEX_INITIALIZER. But what about an static array of them? As, in for example,

#include <pthread.h>
#define NUM_THREADS 5

/*initialize static mutex array*/
static pthread_mutex_t mutexes[NUM_THREADS] = ...?

Or must they be allocated dynamically?

Solution

  • If you have a C99 conforming compiler you can use P99 to do your initialization:

    static pthread_mutex_t mutexes[NUM_THREADS] =
  { P99_DUPL(NUM_THREADS, PTHREAD_MUTEX_INITIALIZER) };

    This just repeats the token sequence PTHREAD_MUTEX_INITIALIZER, the requested number of times.

    For this to work you only have to be sure that NUM_THREADS doesn't expand to a variable but to a decimal integer constant that is visible to the preprocessor and that is not too large.