Visual Studio:回调函数问题(__cdecl *) [英] Visual Studio: Callback function problem (__cdecl *)

问题描述

我有一个在Ubuntu上运行良好的C应用程序，但是我必须将其移植到Visual Studio，这就是问题开始的地方.我正在使用Visual Studio 2017，而我的问题是使用的回调函数.在代码中，我必须注册两个回调函数(几乎相同的代码，只是一个用于发送数据，另一个用于接收数据).

I have a C application that works good on Ubuntu, but I have to port it to Visual Studio, and thats where problems start. I'm using Visual Studio 2017, and my problem is with callback functions that I use. Within the code, I have to register two callback functions (almost the same code, it's just that one is for sending data, other is for receiving it).

libusb_fill_bulk_transfer(recv_transfer_desc,         //transfer descriptor struct
        usb_dev_handle,             //usb device handle
        EP1_IN,                    //unsigned char
        in_buffer,                 //unsigned char*
        len,                        //tranfer length, int
        recv_transfer_finished_cb,  //callback func
        &my_recv_cb_data,           //void*, callback user data
        timeout);                 //unsigned int

这将导致以下错误: C2440'function':无法从'void(__cdecl *)(libusb_transfer *)'转换为'libusb_transfer_cb_fn'

我从不使用VS，所以我真的不知道如何解决此问题.对我来说，它缝起来就像需要将某些东西铸成某种东西，但无法弄清楚.

I never use VS, so I really don't know how to fix this issue. To me it seams like something needs to be casted into something, but just can't figure it out.

这是我要处理的回调函数的签名: static void recv_transfer_finished_cb(struct libusb_transfer *);

This is the signature of callback function I'm trying to handle: static void recv_transfer_finished_cb(struct libusb_transfer *);

推荐答案

我已经弄清楚了，经过反复试验.

I've just figured it out, trough trial and error.

问题在于，VS中的默认调用是 __ cdecl ，并且不能用于回调函数，该回调函数必须是 __ stdcall .

The problem was that default call in VS is __cdecl, and that can't be used for callback functions, which must be __stdcall.

要解决我的问题，我需要将回调函数的签名从以下位置更改:静态无效send_transfer_finished_cb(struct libusb_transfer *); 至: static void __stdcall send_transfer_finished_cb(struct libusb_transfer *);

To solve my problem, I needed to change signature of callback function from: static void send_transfer_finished_cb(struct libusb_transfer *); To: static void __stdcall send_transfer_finished_cb(struct libusb_transfer *);

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