How can I determine whether a process is 32 or 64 bit?

Question

Given a Windows process handle, how can I determine, using C++ code, whether the process is 32 bit or 64 bit?

Answer 1

If you have a process handle, use IsWow64Process().

If IsWow64Process() reports true, the process is 32-bit running on a 64-bit OS.

If IsWow64Process() reports false (or does not exist in kernel32.dll), then the process is either 32-bit running on a 32-bit OS, or is 64-bit running on a 64-bit OS. To know if the OS itself is 32-bit or 64-bit, use GetNativeSystemInfo() (or GetSystemInfo() if GetNativeSystemInfo() is not available in kernel32.dll).

Answer 2

If you have handle to the module then you can do this:

IMAGE_NT_HEADERS * headers = ImageNtHeader(handle);

if ( headers->FileHeader.Machine == IMAGE_FILE_MACHINE_I386 )
{
    //module is x86
}
else if  ( headers->FileHeader.Machine == IMAGE_FILE_MACHINE_AMD64 )
{
    //module is x64
}

I took help from my own answer.

Answer 3

BOOL IsWow64(HANDLE process)
{
    BOOL bIsWow64 = FALSE;

    typedef BOOL(WINAPI *LPFN_ISWOW64PROCESS) (HANDLE, PBOOL);
    LPFN_ISWOW64PROCESS fnIsWow64Process;
    fnIsWow64Process = (LPFN_ISWOW64PROCESS)GetProcAddress(GetModuleHandle(TEXT("kernel32")), "IsWow64Process");

    if (NULL != fnIsWow64Process)
    {
        if (!fnIsWow64Process(process, &bIsWow64))
        {
            //handle error
        }
    }
    return bIsWow64;
}

bool IsX86Process(HANDLE process)
{
    SYSTEM_INFO systemInfo = { 0 };
    GetNativeSystemInfo(&systemInfo);

    // x86 environment
    if (systemInfo.wProcessorArchitecture == PROCESSOR_ARCHITECTURE_INTEL)
        return true;

    // Check if the process is an x86 process that is running on x64 environment.
    // IsWow64 returns true if the process is an x86 process
    return IsWow64(process);
}