C# and PInvoke into 32/64 bit DLL

Question

I am creating a class library, which I hope to put on NuGet eventually. Right now, it is targeting AnyCPU.

I now want to PInvoke into a DLL, which comes in both 32 and 64 bit versions. Initially, I thought I'd just use the 32 bit version, but this threw a BadImageFormatException. I changed the library to target X86 only, and while this works, it requires the caller to be a 32 bit process too. This naturally wouldn't work for a NuGet project.

Appreciate any thoughts on how to work with the 32/64 bit versions of the native library, and how to package this up in NuGet (prefer not to have 2 different assemblies).

Take a look at how SQLite does it. – Cory Nelson May 08 '15 at 04:07 — Cory Nelson, May 08 '15 at 04:07

score 3 · Accepted Answer · edited May 23 '17 at 11:43

You can check platform at runtime and PInvoke into different DLLs.

static void NativeFuncWrapper(){
    if(Environment.Is64BitProcess){
        NativeFuncWrapper64(); //this calls 64-bit dll
    }else{
        NativeFuncWrapper32(); //this calls 32-bit dll
    }
}

If you want it to work without Environment.Is64BitProcess, read How to know a process is 32-bit or 64-bit programmatically for alternative methods.

C# and PInvoke into 32/64 bit DLL

1 Answers1