TITLE.
The function i'm using is this:

void GetVideoCardInfo(int* memoryVar, char* cardName)

{

    strcpy_s(cardName, 128, m_videoCardDescription);

    *memoryVar = m_videoCardMemory;

    return;

}

m_videoCardDescription is a '128 character long' character array that has the description of my video card in it. Here is where I am calling the function:

bool writeGPUnameDesc() {

    char cardDesc;

    int cardMem;

    m_D3D->GetVideoCardInfo(&cardMem, &cardDesc);



    std::ofstream myfile;

    myfile.open("gpuNameAndDesc.txt");

    myfile << "Graphics card name: " << cardDesc;

    myfile << " - Graphics card memory: " << cardMem;

    myfile.close();



    return true;

}

When I run the program a message box pops up that says Runtime-check failure #2
and the title. If anyone can help thanks in advance.

You are copying 128 characters into char cardDesc, which represents only 1 character.

You should change the type of cardDesc to a char-array:

char cardDesc[128];

// ...

m_D3D->GetVideoCardInfo(&cardMem, cardDesc);

//                                ^ no &

TL;DR

std::string GetVideoCardInfo(int & memoryVar)

{

    memoryVar = m_videoCardMemory;

    return m_videoCardDescription;;

}





bool writeGPUnameDesc() {

    int cardMem;

    std::string cardDesc = m_D3D->GetVideoCardInfo(cardMem); 



    std::ofstream myfile;

    myfile.open("gpuNameAndDesc.txt");

    myfile << "Graphics card name: " << cardDesc;

    myfile << " - Graphics card memory: " << cardMem;

    myfile.close();



    return true;

}

Explanation

strcpy_s(cardName, 128, m_videoCardDescription);

is a blatant lie. The size of cardName is exactly one character. If you lie to strcpy_s its extra checking to make sure you don't overrun the buffer cannot help you.

Inferior solutions

Replace

char cardDesc;   

with

char cardDesc[129]; 

The better approach gets rid of the magic numbers entirely.

Up near the top of the file

namespace // annonymous namespace. Contents will not leak out of the file

{

    constexpr int MAX_CARD_NAME_LENGTH = 129 // 128 plus room for nul terminator

}

and then

void GetVideoCardInfo(int* memoryVar, char* cardName)

{

    strcpy_s(cardName, MAX_CARD_NAME_LENGTH, m_videoCardDescription);

    *memoryVar = m_videoCardMemory;

    return;

}

and

bool writeGPUnameDesc() {

    char cardDesc[MAX_CARD_NAME_LENGTH]; // now an array

    int cardMem;

    m_D3D->GetVideoCardInfo(&cardMem, cardDesc); // don't need to take address of array



    std::ofstream myfile;

    myfile.open("gpuNameAndDesc.txt");

    myfile << "Graphics card name: " << cardDesc;

    myfile << " - Graphics card memory: " << cardMem;

    myfile.close();



    return true;

}