C钩子/回调系统
我一直在想如何在C中实现一个hooks系统。有人能给我一些指针或示例吗?使用函数指针:C钩子/回调系统,c,pointers,callback,hook,C,Pointers,Callback,Hook,我一直在想如何在C中实现一个hooks系统。有人能给我一些指针或示例吗?使用函数指针: struct callbacks { void (*somethingHappened)(void *context); bool (*shouldIDoSomething)(void *context); }; void doSomethingAwesome(void *operationData, struct callbacks callbacks) { // context
struct callbacks {
void (*somethingHappened)(void *context);
bool (*shouldIDoSomething)(void *context);
};
void doSomethingAwesome(void *operationData, struct callbacks callbacks)
{
// context is the data you pass to the function
if (callbacks.shouldIDoSomething(context))
{
// do something
callbacks.somethingHappened(context);
}
}
或者,您可以创建调度服务:
struct dictionary
{
char **keys;
void **values;
int count;
};
struct list
{
void **values;
int count;
};
// functions to add, remove, etc;
struct dictionary *callbacks = NULL;
void registerForDispatch(char *key, void (*callback)(void *))
{
if (!callbacks)
{
callbacks = dictionary_create(10); // dictionary with 10 key / value pairs
}
if (!dictionary_containsKey(callbacks, key))
{
struct list *callBacksForKey = list_create(10); // default 10 callbacks, array should be auto-expanding
dictionary_setValue(callbacks, key, arr);
}
struct list *callBacksForKey = dictionary_getValue(callbacks, key);
list_addObject(callBacksForKey, callback);
}
void unregisterFromDispatch(char *key, void (*callback)(void *))
{
struct list *callBacksForKey = dictionary_getValue(callbacks, key);
list_removeObject(callback);
}
void sendNotification(char *key, void *context)
{
struct list *callBacksForKey = dictionary_getValue(callbacks, key);
for (int i = 0; list->count; i++)
{
void (*callback)(void *) = list->values[i];
callback(context);
}
}
使用第二种解决方案,您可以为单个回调使用多个侦听器。您可以看到qsort示例:
/*qsort示例*/
#包括
#包括
int值[]={40,10,100,90,20,25};
整数比较(常数无效*a,常数无效*b)
{
返回(*(int*)a-*(int*)b);
}
int main()
{
int n;
qsort(值,6,sizeof(int),比较);
对于(n=0;n我不确定你到底在寻找什么,但我一直在使用QT/C++中的钩子开发应用程序,所以我可以给你举个小例子
首先,声明函数原型,如下所示
LRESULT CALLBACK LowLevelMouseProc(int nCode, WPARAM wParam, LPARAM lParam);
然后,您需要在main函数中设置钩子,如下所示:
HHOOK mouseHook;
HINSTANCE appInstance = GetModuleHandle(NULL);
mouseHook = SetWindowsHookEx(WH_MOUSE_LL, LowLevelMouseProc, appInstance, 0); //set global mouse hook
然后你需要定义回调函数,我可以给你我的代码>
//Mouse hook callback function.
LRESULT CALLBACK LowLevelMouseProc(int nCode, WPARAM wParam, LPARAM lParam){
if (nCode == HC_ACTION) {
switch(wParam){
case WM_LBUTTONUP:
case WM_RBUTTONUP:
case WM_MOUSEWHEEL:
#ifdef DEBUG
w->printText("Scrolling or click");
#endif
w->save_key("MOUSE");
i++;
break;
default: break;
}
}
return CallNextHookEx(mouseHook, nCode, wParam, lParam);
}
下面是一个指针:<代码> Value*(空)* /代码> .dOpen.考虑支持插件或扩展的应用程序,例如Apache HTTP服务器、LetTPD或浏览器(例如NSAPI)不,那不是指针。那是语法垃圾。@KerrekSB@KerrekSB我想有人会这么说。..xd对于一个大致通用的回调系统,提供上下文的void pointer参数非常有用。那些没有上下文的系统(例如,qsort()
)可能会出现问题-虽然不是每个人都需要qsort()
上下文。请参阅。第二种解决方案是我正在寻找的。我正在编写一个模块化IRC守护程序,不确定如何实现挂钩系统。谢谢!@aarontomasblakely没有问题,请确保接受答案(单击答案旁边的复选标记)。
//Mouse hook callback function.
LRESULT CALLBACK LowLevelMouseProc(int nCode, WPARAM wParam, LPARAM lParam){
if (nCode == HC_ACTION) {
switch(wParam){
case WM_LBUTTONUP:
case WM_RBUTTONUP:
case WM_MOUSEWHEEL:
#ifdef DEBUG
w->printText("Scrolling or click");
#endif
w->save_key("MOUSE");
i++;
break;
default: break;
}
}
return CallNextHookEx(mouseHook, nCode, wParam, lParam);
}