Question

I currently have a class called TextureObject. In the creation function I create the texture, and assign a LPCSTR in the class to a parameter given in the function. When I return that LPCSTR later, it returns in an unexpected manner.

Some type names and functions are from DirectX 11, just ignore them.

Code:

The h File:

class TextureObject
{
public:
    ID3D11ShaderResourceView *pTexture;
    LPCSTR GetFilename() const { return *FFilename; }

    bool IsNotNull;
    void CreateTexture(ID3D11Device &dev,LPCSTR Filename);
    void ReCreate(ID3D11Device &dev);
    void Release();
    int relativeId;
private:
    LPCSTR *FFilename;
};

The cpp file:

void TextureObject::CreateTexture(ID3D11Device &dev,LPCSTR Filename)
{
    D3DX11CreateShaderResourceViewFromFile(
            &dev,        // the Direct3D device
            Filename,    // load Wood.png in the local folder
            NULL,        // no additional information
            NULL,        // no multithreading
            &pTexture,   // address of the shader-resource-view
            NULL);       // no multithreading
    FFilename = new LPCSTR(Filename);
    IsNotNull = true;
}

void TextureObject::ReCreate(ID3D11Device &dev)
{
    CreateTexture(dev, *FFilename);
}

When using vs 2012 debugger in the CreateTexture function, the Filename debugger values are:

0x0a06fed0 "C:\Users\Utilizador\Desktop\particle.png"

Which is perfect for me! When i assign the class’s FFilename:

FFilename = new LPCSTR(Filename);

It’s ok. When I check the value of FFilename within the scope of this function, it’s the same value of the Filename. But when i use GetFilename, things start getting crazy:

 = 0x0a06fed0 "îþîþîþîþîþîþîþîþîþîþîþîþîþîþîþîþîþîþîþîþîþîþîþîþîþîþîþîþîþîþîþîþîþîþîþîþü =I.C"

Mmm, I just met you, and this is crazy, but… Here’s my value. mKay?

Well, please help me. Thank You

Answer 1

You are not copying the string. You are copying the pointer. I think you probably wanted to copy the string, because you cannot guarantee the caller’s pointer will still reference valid data at a later time.

LPCSTR is just a const char*. There’s probably a corresponding windows call, but I would just use strdup to copy the string.

Define FFilename as LPCSTR:

LPCSTR FFilename;

And then:

void TextureObject::CreateTexture(ID3D11Device &dev,LPCSTR Filename)
{
    D3DX11CreateShaderResourceViewFromFile(
            &dev,        // the Direct3D device
            Filename,    // load Wood.png in the local folder
            NULL,        // no additional information
            NULL,        // no multithreading
            &pTexture,   // address of the shader-resource-view
            NULL);       // no multithreading
    FFilename = strdup(Filename);
    IsNotNull = true;
}

void TextureObject::ReCreate(ID3D11Device &dev)
{
    CreateTexture(dev, FFilename);
}

Since you are using C++, you are free to use std::string instead, which will be cleaned up automatically when the object is destroyed.