Linker Tools Warning LNK4227

  • Article

metadata operation warning (HRESULT) : warning_message

The linker detected metadata differences when merging:

  • One or more referenced assemblies with the assembly currently being built.

  • One or more source code files in a compilation.

For example, LNK4227 may be caused if you have two global functions with the same name but parameter information declared differently (declarations are not consistent in all compilands). Use ildasm.exe /TEXT /METADATA object_file on each .obj file and you should see how the types differ.

LNK4227 also reports problems that originate with another tool. For example, al.exe; see Al.exe Tool Errors and Warnings.

The metadata problems must be fixed to resolve the warning.

For example, LNK4227 is generated when a referenced assembly was signed differently than the assembly that references it.

The following sample generates LNK4227:

// LNK4227.cpp
// compile with: /clr
using namespace System::Reflection;

[assembly:AssemblyDelaySignAttribute(false)];

int main() {}

and then,

// LNK4227b.cpp
// compile with: /clr LNK4227.cpp /FeLNK4227b.exe
using namespace System::Reflection;
using namespace System::Runtime::CompilerServices;

[assembly:AssemblyDelaySignAttribute(true)];
// Try the following line instead
// [assembly:AssemblyDelaySignAttribute(false)];

ref class MyClass
{
};

The following sample generates LNK4227:

// LNK4227c.cpp
// compile with: /clr:oldSyntax
#using <mscorlib.dll>
using namespace System::Reflection;

[assembly:AssemblyDelaySignAttribute(false)];

int main() {}

and then,

// LNK4227d.cpp
// compile with: /clr:oldSyntax LNK4227c.cpp /FeLNK4227d.exe
#using <mscorlib.dll>
using namespace System::Reflection;
using namespace System::Runtime::CompilerServices;

[assembly:AssemblyDelaySignAttribute(true)];

__gc class MyClass
{
};

LNK4227 can also be generated when version numbers in the wrong format are passed to assembly attributes. The '*' notation is specific to the AssemblyVersionAttribute. To resolve this warning, use only numbers in the version attributes other than AssemblyVersionAttribute.

The following sample generates LNK4227:

// LNK4227e.cpp
// compile with: /clr /LD /W1
using namespace System::Reflection;
[assembly:AssemblyVersionAttribute("2.3.*")];   // OK
[assembly:AssemblyFileVersionAttribute("2.3.*")];   // LNK4227
// try the following line instead
// [assembly:AssemblyFileVersionAttribute("2.3")];