C++ GeoClue g_object_unref:断言“G_IS_OBJECT(对象)”失败

Question

因此，我最近尝试为我的一个Raspberry项目尝试GeoClue，但我仍然坚持使用gclue-simple()。运行gclue_simple_new似乎很好，但是当我试图用gclue_simple_new_finish()获取指针时，程序会给出一个运行时错误：

(process:37607): GLib-GIO-CRITICAL **: 16:26:33.873: g_async_result_get_source_object: assertion 'G_IS_ASYNC_RESULT (res)' failed

(process:37607): GLib-GIO-CRITICAL **: 16:26:33.873: g_async_initable_init_finish: assertion 'G_IS_ASYNC_INITABLE (initable)' failed

(process:37607): GLib-GObject-CRITICAL **: 16:26:33.873: g_object_unref: assertion 'G_IS_OBJECT (object)' failed

该程序的代码如下：

#include <cstdlib>
#include <iostream>

#include <gclue-simple.h>

void geoclue_callback (GObject* srcObj, GAsyncResult* result, void* userData); 

int main(){
    std::cout << "Program started." << std::endl; 
    
    const char* DESKTOP_ID = "desktop1"; 
    GClueAccuracyLevel accuracy = GCLUE_ACCURACY_LEVEL_CITY; 
    GCancellable* cancellablePtr = NULL; 
    GAsyncReadyCallback callback = geoclue_callback; 
    //gpointer is like void pointer. 
    gpointer usrDataPtr; 

    std::cout << "Variables declared." << std::endl; 

    gclue_simple_new(
        DESKTOP_ID, 
        accuracy, 
        cancellablePtr, 
        callback, 
        usrDataPtr
    ); 

    std::cout << "geoclue service started." << std::endl; 

    GClueSimple* gclueServicePtr; 
    GAsyncResult* rstPtr; 
    GError** errsPtr; 
    //This part here causes runtime error. 
    gclueServicePtr = gclue_simple_new_finish(rstPtr, errsPtr); 

}

void geoclue_callback (GObject* srcObj, GAsyncResult* result, void* userData) { 
    //Callback function for when Geoclue comes up with something
    std::cout << "Results Ready." << std::endl; 
}

我只是进入地理线索，我以前没有任何与gtk或GNOME项目相关的经验，所以我可能遗漏了一些显而易见的东西。

谢谢!

Answer 1

callback不是告诉您某些结果已经准备好，而是告诉您已经创建了GClueSimple*对象。您需要从gclue_simple_new_finish()内部调用callback，而不是在此之前。您需要将GAsyncResult *result传递给它，再加上指向GError *error = NULL初始化错误的指针。

如果初始化失败，gclue_simple_new_finish()可能返回NULL (以及您给它的错误指针中的GError对象)。