Alternative to using macros to change old code

I am trying to rephrase old code with RAII pattern . The old code manages resource allocation but expects users to lock / unlock the resource explicitly. So, for example, something like this (just an example, not real code):

void modify(int id){
    lock();
    modify_data_related_to_id(id);
    unlock();
}

      

        
        
        
      

    

becomes something like this:

void modify(int id){
    RAIIOBJ obj;
    modify_data_related_to_id(id);
}

      

        
        
        
      

    

The advantage is that you don't have to remember the object unlock

. When an item RAIIOBJ

is removed, the unlock will be called automatically in its destructor.

The problem is that there are a ton of places to re-evaluate. I thought I would use macros and replace the call lock

with an RAII call and unlock

become a no-op function, like this:

#define lock() RAIIOBJ obj;
void unlock(){ //empty function
}

      

        
        
        
      

    

This way I don't have to change every place that lock / unlock calls in order to use the RAII method. That said, is there any better way - maybe a template for some problem - to do this than using a macro.