Indicates that a modified method is an intrinsic value for which the just-in-time (JIT) compiler can perform special code generation. This class cannot be inherited.
Assembly: mscorlib (in mscorlib.dll)
Compilers emit custom modifiers within metadata to change the way that the just-in-time (JIT) compiler handles values when the default behavior is not appropriate. When the JIT compiler encounters a custom modifier, it handles the value in the way that the modifier specifies. Compilers can apply custom modifiers to methods, parameters, and return values. The JIT compiler must respond to required modifiers but can ignore optional modifiers.
You can emit custom modifiers into metadata using one of the following techniques:
Generating a Microsoft intermediate language (MSIL) instruction file that contains calls to modopt and modreq, and assembling the file with the Ilasm.exe (MSIL Assembler).
Using the unmanaged reflection API.
Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.