C# Directive to indicate 32-bit or 64-bit build

Question

Is there some sort of C# directive to use when using a development machine (32-bit or 64-bit) that says something to the effect of:

if (32-bit Vista)
    // set a         


        

Answer 1

I am not sure if this is what you are looking for but I check the IntPtr.Size to detect 32bit versus 64bit runtime. Note that this tells you the runtime environment, you might be running in WOW64

if (IntPtr.Size == 4)
{
    //32 bit
}
else if (IntPtr.Size == 8)
{
    //64 bit
}
else
{
    //the future
}