bind

application_->onAppCmd = boost::bind(&GameCore::engine_handle_cmd, ...);

class GameCore {
public:
void engine_handle_cmd(struct android_app* app, int32_t cmd);
}

GameCore gc;
application_->onAppCmd = boost::bind(&GameCore::engine_handle_cmd, gc, ...);

void engine_handle_cmd(struct android_app* app, int32_t cmd);

struct android_app {
    ...    
 
    // Fill this in with the function to process main app commands (APP_CMD_*)
    void (*onAppCmd)(struct android_app* app, int32_t cmd);
 
    ...
}

#include <iostream>
 
struct type {
   type()
      :mptr(0)
   {}
   
   void m(int, const char*) {}
   
   void(type::*mptr)(int, const char*);
};
 
int main() {
   type t;
   std::cout << t.mptr << std::endl;
   t.mptr = &type::m;
   std::cout << t.mptr << std::endl;
}

boost::function2<void, struct android_app*, int32_t> f = boost::function2<void, struct android_app*, int32_t>(
            boost::bind(&GameCore::engine_handle_cmd, this, _1, _2));
 
    application_->onAppCmd = &f;