/platform (C# Compiler Options)
Specifies which version of the common language runtime (CLR) can run the assembly.
x86, Itanium, x64, or anycpu (default).
x86 compiles your assembly to be run by the 32-bit, x86-compatible common language runtime.
Itanium compiles your assembly to be run by the 64-bit common language runtime on a computer with an Itanium processor.
x64 compiles your assembly to be run by the 64-bit common language runtime on a computer that supports the AMD64 or EM64T instruction set.
anycpu (default) compiles your assembly to run on any platform.
On a 64-bit Windows operating system:
Assemblies compiled with /platform:x86 will execute on the 32 bit CLR running under WOW64.
Executables compiled with the /platform:anycpu will execute on the 64 bit CLR.
DLLs compiled with the /platform:anycpu will execute on the same CLR as the process into which it is being loaded.
For more information about developing an application to run on a Windows 64-bit operating system, see 64-bit Applications.
To set this compiler option in the Visual Studio development environment
Open the Properties page for the project.
Click the Build property page.
Modify the Platform target property.
Note /platform is not available in the development environment in Visual C# Express.
For information on how to set this compiler option programmatically, see PlatformTarget.
The following example shows how to use the /platform option to specify that the application should only be run by the 64-bit CLR on a 64-bit Windows operating system for Itanium.
csc /platform:Itanium myItanium.cs