SUMMARY

There are six types of reusable libraries:

• Static Single Threaded Library (Debug/Release)
• Static Multithreaded Library (Debug/Release)
• Dynamic Link Library (DLL)(Debug/Release)

Note Each library has a debug version and a release version.

The DLL is multithread-safe and a single-thread version of the CRT library is not provided for DLLs. If the reusable library or any user of the library is using multiple threads, then the library needs to be a multithread-safe library type. 

Note Debug libraries and compiler switches /MLd, /MTd, and /MDd are only available in Visual C++ versions 4.0 and later. 

The following table shows which compiler switch should be used for building each of the six types of reusable libraries (all DLL types are multithread-safe). Any project that uses the reusable library should use the same compiler switch. When using the /ML(default), /MLd, /MT, /MTd, /MD, or /MDd compiler switches, the compiler places the default library name (listed under the Library column) in the object file.

Reusable Library            Switch    Library    Macro(s) Defined
----------------------------------------------------------------
Single Threaded             /ML       LIBC       (none)
Static MultiThread          /MT       LIBCMT     _MT
Dynamic Link (DLL)          /MD       MSVCRT     _MT and _DLL
Debug Single Threaded       /MLd      LIBCD      _DEBUG
Debug Static MultiThread    /MTd      LIBCMTD    _DEBUG and _MT
Debug Dynamic Link (DLL)    /MDd      MSVCRTD    _DEBUG, _MT, and _DLL
				

You can view an object module to determine which switch was used when it was built by using this command:

   dumpbin /all <object>.obj
				

Look in the section titled RAW DATA #1. In the right-most column, the default libraries will be listed.