ç回调和非围棋线程 [英] C callbacks and non-Go threads

问题描述

1. 如何从线程用C一个呼叫转到code，它不是由围棋产生的？


2. 我怎么分配给一个C函数指针，这样不会被转到创建的线程可以调用该指针，进入围棋code？

• 我不希望使用痛饮。


• 的回调将线程进入以前没有见过到来。无论是 CGO /生活，也没有任何东西包装/运行演示此行为AFAICT。

Update0

• I don't want to use SWIG.
• The callbacks will be coming from threads Go hasn't seen before. Neither cgo/life nor anything in pkg/runtime demonstrates this behaviour AFAICT.

推荐答案

您可以这样做，但解决方案是相对较慢（大约每次通话22μs我的机器上）。
答案是为C code用C线与原语将实际运行回调的另一个够程进行通信。

You can do this, but the solution is relatively slow (about 22µs per call on my machine). The answer is for the C code to use C thread primitives to communicate with another goroutine that will actually run the callback.

我创建了一个围棋包提供此功能：的 rog-go.google code.com / HG / EXP /回调。
有一个例子包证明其使用的此处。示例说明从转到运行之外创建一个线程回调到任意转到关闭。另一个例子是这里。这说明一个典型的C回调接口和层在它上面一个围棋回调。

I have created a Go package that provides this functionality: rog-go.googlecode.com/hg/exp/callback. There is an example package demonstrating its use here. The example demonstrates a call back to an arbitrary Go closure from a thread created outside of the Go runtime. Another example is here. This demonstrates a typical C callback interface and layers a Go callback on top of it.

要尝试的第一个例子：

goinstall rog-go.googlecode.com/hg/exp/example/looper
cd $GOROOT/src/pkg/rog-go.googlecode.com/hg/exp/example/looper
gotest

要尝试第二个例子：

goinstall rog-go.googlecode.com/hg/exp/example/event
cd $GOROOT/src/pkg/rog-go.googlecode.com/hg/exp/example/event
gotest

这两个例子都假设pthreads的是可用的。当然，这只是一个权宜之计，直到CGO是固定的，但对于任意调用关闭围棋在C回调将适用即使在当时的技术。

Both examples assume that pthreads are available. Of course, this is just a stop-gap measure until cgo is fixed, but the technique for calling arbitrary Go closures in a C callback will be applicable even then.

下面是回调包的文档：

PACKAGE

package callback
import "rog-go.googlecode.com/hg/exp/callback"

变量

var Func = callbackFunc

Func键存放一个指针到C回调函数。
在调用时，它调用在所提供的函数f
围棋方面与给定的参数。

Func holds a pointer to the C callback function. When called, it calls the provided function f in a a Go context with the given argument.

它可以通过首先将其转换为一个函数指针被用于
然后从C主叫
下面是设置了回调函数的例子：

It can be used by first converting it to a function pointer and then calling from C. Here is an example that sets up the callback function:

//static void (*callback)(void (*f)(void*), void *arg);
//void setCallback(void *c){
//  callback = c;
//}
import "C"
import "rog-go.googlecode.com/hg/exp/callback"

func init() {
    C.setCallback(callback.Func)
}

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