CreateThread Wrapper Function

Question

I am currently working on a project where we have a C thread implementation for UNIX systems using pthreads. Now we want to be able to run this entire project on Windows, as well as translate all threads for WIN32. Now I am faced with a problem for which I could not come up with a decent solution.

I have a function thrd_create():

static inline int thrd_create(thrd_t *thr, thrd_start_t func, void *arg) {
    Args* args = malloc(sizeof(Args));
    args->arg = arg;
    args->function = func;
    *thr = CreateThread(NULL, 0, wrapper_function, (LPVOID) args, 0, NULL);
    if (!*thr) {
        free (args);
        return thrd_error;
    }
    return thrd_success;
}

This function should create a new thread, and the user provides a start function. For convenience, I would like to leave the implementation that calls thrd_create () intact, if possible. For this reason, I created wrapper_function:

static inline DWORD wrapper_function(LPVOID arg) {
    Args * args;
    args = (Args*) arg;
    DWORD res = args->function(args->arg); //This does obviously not work
    return res;
}

: DWORD ? , pthread, void, . ?

Args :

struct Args {
    void (*function)(void * aArg);
    void* arg;
};
typedef struct Args Args;

Answer 1

:

• Windows
• Pthreads

, , args, , , , .

API - :

/* Your general error codes enumeration
 * which should probably reside in a general
 * header 
 */
typedef enum {
  OK = 0,
  // Your application specific error codes
} error_t;

#ifdef _WIN32
  #include <Windows.h>
  typedef HANDLE thread_handle_t;
#else // assume pthreads
  #include <pthread.h>
  typedef pthread_t thread_handle_t;
#endif

typedef error_t(*entry_func_t)(void*);

typedef struct {
  entry_func_t     func;
  void             *args;
  error_t          _result;
  thread_handle_t  _handle;
} thread_t;

// returns OK(0) on success
// returns error code indicating a problem
error_t thread_create(thread_t *t);

:

#ifdef _WIN32
  DWORD _win_entry_f(void *args) {
    thread_t *t = args;
    t->_result = t->func(t->args);
    return 0; // Or some other Windows-specific value
  }

  error_t thread_create(thread_t *t) {
    error_t err = OK;
    if(!(t->_handle = ThreadCreate(NULL, 0, _win_entry_f, t, 0, NULL))) {
      switch (GetLastError()) {
        // Populate error with code
      }
    }
    return err;
  }
#else
  void * _pthread_entry_f(void *args) {
    thread_t *t = args;
    t->_result = t->func(t->args);
    return NULL; // Or some other pthreads specific value
  }

  error_t thread_create(thread_t *t, entry_func_t func, void *args) {
    error_t err = OK;
    switch(pthread_create(&t->_handle, NULL, _pthread_entry_f, t)) {
    case 0: break;
    // other cases populate err
    }
    return err;
  }
#endif

Invokation .

error_t func(void* args) {
  return OK;
}

.....................

thread_t t = { .func = func, .args = NULL };
thread_create(&t);

, , , ,...