AnyCPU

https://stackoverflow.com/questions/5229768/c-sharp-compiling-for-32-64-bit-or-for-any-cpu

On a 32-bit machine:

• Any CPU: runs as a 32-bit process, can load Any CPU and x86 assemblies, will get BadImageFormatException if it tries to load an x64 assembly.

• x86: same as Any CPU.

• x64: BadImageFormatException always.

On a 64-bit machine:

• Any CPU: runs as a 64-bit process, can load Any CPU and x64 assemblies, will get BadImageFormatException if it tries to load an x86 assembly.

• x86: runs as a 32-bit process, can load Any CPU and x86 assemblies, will get BadImageFormatException if it tries to load an x64 assembly.

• x64: same as Any CPU.

It is the JIT compiler that generates an assembly code that's compatible with the requested target based on this flag.