Converting projects from mixed mode to pure intermediate language

All Visual C++ CLR projects link to the C run-time libraries by default. As a result, these projects are classified as mixed-mode applications, because they combine native code with code that targets the common language runtime (managed code). When they're compiled, they get compiled into intermediate language (IL), also known as Microsoft intermediate language (MSIL).

If you're using an earlier version of the Microsoft C++ compiler toolset that supports /clr:pure or /clr:safe, you can use this procedure to convert your code to pure MSIL:

To convert your mixed-mode application into pure intermediate language

1. Remove links to the C runtime libraries (CRT):

   1. In the .cpp file defining the entry point of your application, change the entry point to Main(). Using Main() indicates that your project doesn't link to the CRT.

   2. In Solution Explorer, right-click your project and select Properties on the shortcut menu to open the property pages for your application.

   3. In the Advanced project property page for the Linker, select the Entry Point and then enter Main in this field.

   4. For console applications, in the System project property page for the Linker, select the SubSystem field and change it to Console (/SUBSYSTEM:CONSOLE).

      Note

      You don't have to set this property for Windows Forms applications because the SubSystem field is set to Windows (/SUBSYSTEM:WINDOWS) by default.

   5. In stdafx.h, comment out all the #include statements. For example, in console applications:

      // #include <iostream>
      // #include <tchar.h>
      

      -or-

      For example, in Windows Forms applications:

      // #include <stdlib.h>
      // #include <malloc.h>
      // #include <memory.h>
      // #include <tchar.h>
      

   6. For Windows Forms applications, in Form1.cpp, comment out the #include statement that references windows.h. For example:

      // #include <windows.h>
      

2. Add the following code to stdafx.h:

   #ifndef __FLTUSED__
   #define __FLTUSED__
      extern "C" __declspec(selectany) int _fltused=1;
   #endif
   

3. Remove all unmanaged types:

   Wherever appropriate, replace unmanaged types with references to structures from the System namespace. Common managed types are listed in the following table:

   Structure	Description
   Boolean	Represents a Boolean value.
   Byte	Represents an 8-bit unsigned integer.
   Char	Represents a Unicode character.
   DateTime	Represents an instant in time, typically expressed as a date and time of day.
   Decimal	Represents a decimal number.
   Double	Represents a double-precision floating-point number.
   Guid	Represents a globally unique identifier (GUID).
   Int16	Represents a 16-bit signed integer.
   Int32	Represents a 32-bit signed integer.
   Int64	Represents a 64-bit signed integer.
   IntPtr	A platform-specific type that is used to represent a pointer or a handle.
   SByte	Represents an 8-bit signed integer.
   Single	Represents a single-precision floating-point number.
   TimeSpan	Represents a time interval.
   UInt16	Represents a 16-bit unsigned integer.
   UInt32	Represents a 32-bit unsigned integer.
   UInt64	Represents a 64-bit unsigned integer.
   UIntPtr	A platform-specific type that is used to represent a pointer or a handle.
   Void	Indicates a method that doesn't return a value; that is, the method has the void return type.