GetWindowCompositionAttribute

Retreives various information about DWM window attributes

Syntax

BOOL WINAPI GetWindowCompositionAttribute (
    HWND hwnd,
    WINCOMPATTRDATA* pAttrData
)

Parameters

Return Value

Nonzero on success, zero otherwise. Call GetLastError on failure for more information.

Remarks

The layout of the WINCOMPATTRDATA structure is :

struct WINCOMPATTRDATA
{
    DWORD attribute; // the attribute to query, see below
    PVOID pData; // buffer to store the result
    ULONG dataSize; // size of the pData buffer
};

This function is identical to DwmGetWindowAttribute with the exception that the parameters after the HWND are packed in a struct, rather than passed individually.

Most of the attributes passed to DwmGetWindowAttribute can be used unchanged, however DWMWA_DISALLOW_PEEK and DWMWA_EXCLUDED_FROM_PEEK use values 0x11 and 0xe instead.

The other difference is that some of the attributes have different values

This function is also known as NtUserGetWindowCompositionAttribute.

Examples

// Note this sample requires DWM to be enabled
#include <windows.h>
#include <dwmapi.h>
#include <stdio.h>

struct WINCOMPATTRDATA
{
    DWORD attribute;
    PVOID pData;
    ULONG dataSize;
};

void PrintMessage(BOOL bEnabled)
{
    printf("NC Rendering Enabled for console window: %d\n", bEnabled);
}

DWORD TranslateDWMAttribute(DWORD dwmAttr)
{
    if(dwmAttr < DWMWA_DISALLOW_PEEK) return dwmAttr;
    if(dwmAttr == DWMWA_DISALLOW_PEEK) return 0x11;
    if(dwmAttr == DWMWA_EXCLUDED_FROM_PEEK) return 0xe;
}

int main()
{
    typedef BOOL (WINAPI*pfnGWA)(HWND, WINCOMPATTRDATA*);
    HMODULE hMod = LoadLibrary(L"user32.dll");
    pfnGWA getWindowAttribute = (pfnGWA)GetProcAddress(hMod, "GetWindowCompositionAttribute");

    HWND hwndCon = GetConsoleWindow();
    BOOL renderingEnabled = FALSE;

    HRESULT hr = DwmGetWindowAttribute(hwndCon, DWMWA_NCRENDERING_ENABLED, &renderingEnabled, sizeof(renderingEnabled));
    if(SUCCEEDED(hr))
    {
        PrintMessage(renderingEnabled);
    }
    else
    {
        printf("DGWA failed with error %#x\n", hr);
    }

    renderingEnabled = FALSE;
    DWORD attributeVal = TranslateDWMAttribute(DWMWA_NCRENDERING_ENABLED);
    WINCOMPATTRDATA attrData = {attributeValue, &renderingEnabled, sizeof(renderingEnabled)};
    BOOL gwaRet = getWindowAttribute(hwndCon, &attrData);
    if(gwaRet)
    {
        PrintMessage(renderingEnabled);
    }
    else
    {
        printf("GWA failed with error %lu\n", GetLastError());
    }
    FreeLibrary(hMod);
    return 0;
}