Indicates whether a multithreaded module is a DLL and specifies retail or debug versions of the runtime library.

Syntax

/MD[d]
/MT[d]
/LD[d]
Remarks
Option
Description
Use the multithread-specific and DLL-specific version of the runtime library. Defines _MT and _DLL. The linker uses the MSVCRT.lib import library to resolve runtime symbols.
Use the debug multithread-specific and DLL-specific version of the runtime library. Defines _DEBUG, _MT, and _DLL. The linker uses the MSVCRTD.lib import library to resolve runtime symbols.
Use the multithread, static version of the runtime library. Defines _MT. The linker uses LIBCMT.lib to resolve runtime symbols.
Use the debug multithread, static version of the runtime library. Defines _DEBUG and _MT. The linker uses LIBCMTD.lib to resolve runtime symbols.
Create a DLL.

 Passes the /DLL option to the linker. The linker looks for, but does not require, a DllMain function. If you don't write a DllMain function, the linker inserts a DllMain function that returns TRUE.

 Links the DLL startup code.

 Creates an import library (.lib), if an export (.exp) file is not specified on the command line. You link the import library to applications that call your DLL.

 Interprets /Fe (Name EXE File) as naming a DLL rather than an .exe file. By default, the program name becomes basename.dll instead of basename.exe.

 Implies /MT unless you explicitly specify /MD.
Create a debug DLL. Defines _MT and _DEBUG.
For more information about C runtime libraries and which libraries are used when you compile with /clr (Common Language Runtime Compilation), see CRT Library Features.
All modules passed to a given invocation of the linker must have been compiled with the same runtime library compiler option (/MD, /MT, /LD).
For more information about how to use the debug versions of the runtime libraries, see  C runtime Library Reference.
For more about DLLs, see Create C/C++ DLLs in Visual Studio.
To set this compiler option in the Visual Studio development environment
Open the project's Property Pages dialog box. For details, see Set C++ compiler and build properties in Visual Studio.
Select the Configuration Properties > C/C++ > Code Generation property page.
Modify the Runtime Library property.
To set this compiler option programmatically
See RuntimeLibrary.
See also
MSVC Compiler Options

MSVC Compiler Command-Line Syntax

The Great C Runtime (CRT) Refactoring