通过引用将向量传递给类

Question

I have a vector of ofTextures called images. I want to pass this to a class called Section by reference so it is not copied.

images is created in the header file. images has textures created inside of it, in the draw method with:

void ofApp::draw(){
if (video0.isFrameNew()){
    ofPixels pixels = video0.getPixels();
    images.emplace_back();
    images.back().allocate(pixels);
    }
}

I have a getTextures() function to return my images by reference I think the vector should still exist as I have initialised it before using it in this function.

vector<ofTexture> &ofApp::getTextures(){
    return  images;
}

I use this in the call to my constructor which is in a for loop in void ofApp::setup()

imSec.push_back(Section(getTextures());

I use getTextures() to pass the vector into my call to my constructor; however, when I run my program I don't seem to be able to draw the contents of the vector as I don't think my reference to the vector is working.

Any help on the correct way to pass by reference would be great.

Answer 1

The function getTexture() must return a reference to a vector that exists after the function returns. If you declare a vector inside that function and return a reference to it, it will not work, since the vector's memory in invalidated after the function returns.