Question

Hello stackoverflow fellow members?

Struct Declaration in class A

struct PointSprite 
{
    GLfloat x;
    GLfloat y;
    GLfloat size;
    Color4f color;
} ParticleSystems[MAXIMUM_PARTICLES_ON_SCREEN];
// I generally put some stuffs in ParticleSystem array. 
// for ex) struct PointSprite *ps = &ParticleSystems[index];
// and it works well on the class A, but I want to get class B to access this array.

My question is, how am I suppose be return the array of ‘ParticlelSystems‘ array so that other class can access to it? I have tried below code to return the pointer, but compiler gives me a warning.

- (struct ParticleSystems *) commitParticles
{
    struct ParticleSystems *ptr = &ParticleSystems; // it said, assigning incompatible pointer type
    
    return ptr;
}

Or should I need to allocate the ‘ParticleSystems‘ array? Please help ! Thanks

Answer 1

If you are creating the array inside the function then you should dynamically allocate it using new and then return a pointer to it.

You cannot return arrays from a function, you will have to return a pointer to it.

Sample Code:

ParticleSystems* doSomethingInteresting()
{
    ParticleSystems *ptr = new ParticleSystems[MAXIMUM_PARTICLES_ON_SCREEN];

    //do the processing

    return ptr;

}

The caller takes the ownership of the returned dynamically allocated array and needs to deallocate it to avoid memory leaks:

delete []ptr;