如何在需要C风格回调的函数中使用std ::函数？
如果不可能,下一件最好的事情是什么？
例：
// --- some C code I can not change ---
typedef void(*fun)(int);
void register_callback(fun f) {
f(42); // a test
}
// ------------------------------------
#include <functional>
#include <iostream>
void foo(const char* ptr,int v,float x) {
std::cout << ptr << " " << v << " " << x << std::endl;
}
int main() {
std::function<void(int)> myf = std::bind(&foo,"test",std::placeholders::_1,3.f);
register_callback(myf); // <-- How to do this?
}
解决方法
长答案：您可以编写一个C函数传递给调用您的std ::函数的API：
// --- some C code I can not change ---
typedef void(*fun)(int);
void register_callback(fun f) {
f(42); // a test
}
// ------------------------------------
#include <functional>
#include <iostream>
void foo(const char* ptr,float x) {
std::cout << ptr << " " << v << " " << x << std::endl;
}
namespace {
std::function<void(int)> callback;
extern "C" void wrapper(int i) {
callback(i);
}
}
int main() {
callback = std::bind(&foo,3.f);
register_callback(wrapper); // <-- How to do this?
}
