Question

This method causes an abort error: "map/set iterator not incrementable."
Due to that after the if fails and a vaild iterator that should be erased is determined, (and is), continuing to the next iterator in the map via ++_iter fails because _iter is no longer a valid object/pointer.

What is the correct procedure for iterating through a map AND having the ability to remove individual items throughout?

typedef std::map<std::string, BITMAP*> MapStrBmp;
typedef MapStrBmp::iterator MapStrBmpIter;
\\...
void BitmapCache::CleanCache() {
    //Clean the cache of any NULL bitmaps that were deleted by caller.
    for(MapStrBmpIter _iter = _cache.begin(); _iter != _cache.end(); ++_iter) {
        if(_iter->second != NULL) {
            if((_iter->second->w < 0 && _iter->second->h < 0) == false) continue;
        }
        _cache.erase(_iter);
    }
}

Answer 1

You just have to be a bit more careful:

void BitmapCache::CleanCache() {
    //Clean the cache of any NULL bitmaps that were deleted by caller.
    for(MapStrBmpIter _iter = _cache.begin(); _iter != _cache.end(); ) {
        if(_iter->second != NULL) {
            if((_iter->second->w < 0 && _iter->second->h < 0) == false)
            {
                ++_iter;
                continue;
            }
        }

        _cache.erase(_iter++);
    }
}