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IsSignUnspecifiedByte Class

Indicates that a modifier is neither signed nor unsigned. This class cannot be inherited.


Namespace:  System.Runtime.CompilerServices
Assembly:  mscorlib (in mscorlib.dll)

public static class IsSignUnspecifiedByte

Some programming languages, such as C++, recognize three distinct char values: signed char, unsigned char, and char. To distinguish the unmodified char type from the others, the Microsoft C++ compiler adds the IsSignUnspecifiedByte modifier to each char type emitted to an assembly.

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:

The following code example creates an assembly using classes in the System.Reflection.Emit namespace and emits the IsSignUnspecifiedByte modifier into that assembly.

#using <mscorlib.dll>

using namespace System;
using namespace System::Reflection;
using namespace System::Reflection::Emit;
using namespace System::Runtime::CompilerServices;
using namespace System::Threading;

ref class CodeEmitter
    AssemblyBuilder^ asmBuilder;
    String^ asmName;
    ModuleBuilder^ modBuilder;

    void prepareAssembly(String^ name){

        // Check the input.

            throw gcnew ArgumentNullException("AssemblyName");

        asmName = name;

        // Create an AssemblyName object and set the name.
        AssemblyName^ asmName = gcnew AssemblyName();

        asmName->Name = name;

        // Use the AppDomain class to create an AssemblyBuilder instance.

        AppDomain^ currentDomain = Thread::GetDomain();

        asmBuilder = currentDomain->DefineDynamicAssembly(asmName,AssemblyBuilderAccess::RunAndSave);

        // Create a dynamic module.
        modBuilder = asmBuilder->DefineDynamicModule(name);


    // Constructor.
    CodeEmitter(String ^ AssemblyName){


    // Create a new type.
    TypeBuilder^ CreateType(String^ name){

        // Check the input.

            throw gcnew ArgumentNullException("AssemblyName");

        return modBuilder->DefineType( name );

    // Write the assembly.
    void WriteAssembly(MethodBuilder^ entryPoint){

        // Check the input.

            throw gcnew ArgumentNullException("entryPoint");

        asmBuilder->SetEntryPoint( entryPoint );
        asmBuilder->Save( asmName );


void main()

    // Create a CodeEmitter to handle assembly creation.
    CodeEmitter ^ e = gcnew CodeEmitter("program.exe");

    // Create a new type.
    TypeBuilder^ mainClass = e->CreateType("MainClass");

    // Create a new method.
    MethodBuilder^ mBuilder = mainClass->DefineMethod("mainMethod", MethodAttributes::Static);

    // Create an ILGenerator and emit IL for 
    // a simple "Hello World." program.
    ILGenerator^ ilGen = mBuilder->GetILGenerator();

    ilGen->Emit(OpCodes::Ldstr, "Hello World");

    array<Type^>^mType = {String::typeid};

    MethodInfo^ writeMI = Console::typeid->GetMethod( "WriteLine", mType );

    ilGen->EmitCall(OpCodes::Call, writeMI, nullptr );

    ilGen->Emit( OpCodes::Ret );

    // Apply a required custom modifier
    // to a field.

    array<Type^>^fType = {IsSignUnspecifiedByte::typeid};

    mainClass->DefineField("modifiedInteger", Type::GetType("System.Byte"), fType, nullptr, FieldAttributes::Private);

    // Create the type.

    // Write the assembly using a reference to 
    // the entry point.

    Console::WriteLine(L"Assembly created.");

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.