回调宏(QT) [英] CALLBACK macro (QT)

问题描述

我有一个带有这样签名的函数

I've got a function with a signature like this

int iV_SetSampleCallback(pDLLSetSample pSampleCallbackFunction)  

pDLLSetSample在哪里

typedef int (CALLBACK * pDLLSetSample) (struct SampleStruct rawDataSample);

我想将我的成员函数作为回调传递

I want to pass my member function as callback

int sampleCallbackFunction(struct SampleStruct sample);

当我这样称呼

iV_SetSampleCallback(&MainWindow::sampleCallbackFunction);

我遇到了错误

error: C2664: 'int iV_SetSampleCallback(pDLLSetSample)': cannot convert argument 1 from 'int (__thiscall MainWindow::* )(SampleStruct)' to 'pDLLSetSample'

我不明白为什么会这样. CALLBACK宏是什么? __thiscall是从哪里来的?我应该如何正确地将回调传递给该函数?

And I can't understand why it happens. What is CALLBACK macro is? Where is __thiscall came from? How should I correctly pass my callback to this function?

推荐答案

发生错误是因为您试图将指针传递给非静态类成员函数sampleCallbackFunction，而不是传递给常规函数的指针.请注意，非静态类成员函数具有显式的this参数. CALLBACK宏通常在Windows中使用，通常代表stdcall调用约定.

Your error is occurring because you are trying to pass a pointer to a non-static class member function sampleCallbackFunction instead of a pointer to a regular function. Note that non-static class member functions have explicit this parameter. CALLBACK macro is often used in Windows and typically stands for stdcall calling convention.

要解决此错误，您需要

• 将成员回调函数声明为静态
• 将CALLBACK宏添加到成员函数之前，以便具有预期的调用约定(或将CALLBACK扩展为的任何内容)

static int CALLBACK sampleCallbackFunction(struct SampleStruct sample);

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