Question

#include <iostream>
#include <windows.h>
using namespace std;

int main(){
    LPWSTR test = L"C:/aizen.png";
    int result = SystemParametersInfo(SPI_SETDESKWALLPAPER, 0, test, SPIF_UPDATEINIFILE);
    if(result)
        cout << "Wallpaper set!";
    else
        cout << "NOOOOO!" << result;
    cin >> result;
    return 0;
}

Very simple code, but result returns 0. What am I doing wrong?

Answer 1

Do what the documentation says, and call GetLastError to find out the reason behind the error.

Some possible causes spring to mind:

• SystemParametersInfo does not like forward slashes as separators.
• The system doesn’t like .png files for wallpaper.
• The file doesn’t exist.
• You have an ANSI/Unicode encoding mismatch.
• You don’t have rights to modify the wallpaper.

Really, the list is endless. So let the system tell you.

---

Note that the documentation says:

When the SPI_SETDESKWALLPAPER flag is used, SystemParametersInfo always returns TRUE.

But this is a great big fat lie. It’s trivially easy to call the function, pass SPI_SETDESKWALLPAPER, and receive FALSE in return.