用Emscripten调用函数指针 [英] Calling a function pointer with Emscripten
问题描述
使用Emscripten，是否可以从JavaScript调用函数指针(因此为数字)?
该函数的签名是可变的，因此我无法编写帮助程序.
With Emscripten, is it possible to call a function pointer (thus, a number) from JavaScript?
The signature of the function is variable, so I can't write a helper and be done.
为了说明一个例子，我有一个像这样的函数:
To illustrate an example, I've got a function like this:
// Returns a function pointer to call, with the appropiate
// arguments, to initialize the demanded feature.
void* get_feature_activator(feature_t feat);
您应该按以下方式使用它:
You're supposed to use it as follows:
// Initialize the speaker
void* activator = get_feature_activator(FEATURE_SPEAKER);
// We know this function needs one float, so we cast and call it
((void(*)(float))activator) (3.0);
要对JavaScript执行相同操作:
To do the same with JavaScript:
var activator = _get_feature_activator(constants.FEATURE_SPEAKER);
// TODO: Need to call this pointer with one float
推荐答案
您可以使用 Runtime.dynCall 从JS调用C函数指针.例如参见
You can call a C function pointer from JS using Runtime.dynCall. See for example
参数是(类型签名，指针，参数数组).例如，类型"vi"表示返回void，接收一个整数参数.这对应于您可以在生成的代码中看到的FUNCTION_TABLE_vi.
The arguments are (type signature, pointer, array of arguments). For example, the type 'vi' means return void, receive one integer parameter. This corresponds to FUNCTION_TABLE_vi which you can see in the generated code.
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