英文:
Windows Hooks with golang
问题
我正在编写一个应用程序，将利用Win32 API的WH_KEYBOARD钩子，以便在没有焦点的情况下激活（即在前台显示）。回调函数自然是一个函数指针（类型为HOOKPROC）。关于WH_KEYBOARD和WH_KEYBOARD_LL的许多文档都说回调函数必须驻留在DLL中，而不能直接在EXE中，但我发现在Windows XP及以上版本中并非如此，所以我认为这是一个历史上的怪癖。
该应用程序是用Go语言编写的。我知道（并且已经为之做出了贡献）github.com/AllenDang/w32，但我没有看到可以用来处理函数指针的东西。由于goroutine的结构，这种操作是否可行？我知道从Go中调用C很简单，但对于这样的回调函数，该怎么处理函数指针呢？
目前，我使用的方法是编写一个通过标准输出发送消息的EXE，将其单独编译，使用go-bindata将其包含进来，并在运行时将其写入临时文件并执行它，同时一个goroutine监视该进程的标准输出。这让我感到不舒服。请告诉我有没有更好的方法，而不使用外部进程和糟糕的IPC技巧。
英文:
I'm writing an application that will make use of the Win32 API WH_KEYBOARD hook so that it can be activated (i.e., displayed in the foreground) without having focus. The callback, naturally, is a function pointer (of type HOOKPROC). A lot of the documentation for WH_KEYBOARD and WH_KEYBOARD_LL says that the callback has to reside in a DLL and cannot directly be in an EXE, however I've found that not to be true in Windows XP and above so I think that's a historical quirk.
The application is written in Go. I'm aware of (and have contributed to) github.com/AllenDang/w32, but I don't see anything that can be used to deal with function pointers. Due to the structure of goroutines, is this even possible? I know that calling C from Go is simple, but what does one do about function pointers for callbacks like this?
Right now my kludge is to write an EXE that sends a message via the standard output, compile it separately, include it using go-bindata and at runtime write this to a temporary file and execute it, while a goroutine watches that process's standard output. It makes me cringe. Please tell me there's a better way without using an external process and awful IPC hackery.
1: https://github.com/AllenDang/w32 "AllenDang/w32"
答案1
得分: 4
请阅读关于cgo的维基页面。
你需要在C中定义回调函数，然后从中调用你的Go函数：
首先导出你的Go回调函数：
//export gocb
func gocb() {
}
然后在hook.c中定义你的回调函数：
#include "_cgo_export.h"
void c_callback() {
gocb();
}
这是一个（非常丑陋的）示例：https://github.com/OneOfOne/go-nfqueue/blob/master/nfqueue.go#L129，https://github.com/OneOfOne/go-nfqueue/blob/master/nfqueue.h和https://github.com/OneOfOne/go-nfqueue/blob/master/nfqueue.c#L49
英文:
Read the wiki page about cgo.
You will have to define the callback in C and then call your Go function from it:
First export your Go callback :
//export gocb
func gocb() {
}
Then define your callback in say hook.c
#include "_cgo_export.h"
void c_callback() {
gocb();
}
It's my code and I hacked it up to test something, never had the time to clean it up after that.
Here's an (ugly ugly) example: https://github.com/OneOfOne/go-nfqueue/blob/master/nfqueue.go#L129, https://github.com/OneOfOne/go-nfqueue/blob/master/nfqueue.h and https://github.com/OneOfOne/go-nfqueue/blob/master/nfqueue.c#L49
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