Question

I’ve been trying to implement a Gearman worker with their C API (libgearman). But their documentation for the C API is poor and not complete. Although its very similar to creating workers in other languages such as PHP, I am still unable to Register a function in the worker via *gearman_worker_add_function();*

To be specific, I am unable to find out how to create an object of *gearman_worker_fn* .

Thanks!

Answer 1

According to this documentation:

typedef void*( gearman_worker_fn)(gearman_job_st *job, void *context,
size_t *result_size, gearman_return_t *ret_ptr)

Definition at line 407 of file constants.h.

This is a function pointer typedef: Basically you just need to create a function with the correct signature (returns void *, takes in gearman_job_st *, void *, size_t *, gearman_return_t *), and then pass in the function name.

Example:

void *do_work(gearman_job_st *job, void *context, size_t *result_size, gearman_return_t *ret_ptr)
{
    do_something();
}

/* Later... */

    gearman_worker_add_function(worker, function_name, timeout, do_work, context);

Notice that I just pass the function name– this degrades to a “function pointer”.