INFO: What Are the C/C++ Libraries My Program Would Link With?

ID: Q154753

The information in this article applies to:

Microsoft Visual C++, 32-bit Editions, versions 4.2, 5.0

SUMMARY

This article describes the default libraries LIBC[D].LIB, LIBCMT[D].LIB, LIBCI[D].LIB, LIBCIMT[D].LIB, LIBCP[D].LIB, LIBCPMT[D].LIB, MSVCRT[D].LIB, MSVCIRT[D].LIB, and MSVCPRT[D].LIB that a program will link with when built using Visual C++.

MORE INFORMATION

When you build a release (or debug) version of your project in Visual C++, one of the basic C Runtime libraries (LIBC[D].LIB, LIBCMT[D].LIB, and MSVCRT[D].LIB) is linked by default, depending on the compiler option you choose (single-threaded <ML[d]>, multithreaded <MT[d]>, or multithreaded DLL<MD[d]>). A library from the Standard C++ Library or one from the old iostream library may also be linked depending on the headers you use in your code. For example, consider the following cases:

Case 1: Sample program test1.cpp


// test1.cpp
void main()
{
}

If you build test.cpp using the /ML (or /MLd, for a debug build) compiler option, your program will link with LIBC.LIB (or LIBCD.LIB, for debug build), in addition to other libraries.

If you build test.cpp using the /MT (or /MTd, for a debug build) compiler option, your program will link with LIBCMT.LIB (or LIBCMTD.LIB, for debug build), in addition to other libraries.

If you build test.cpp using the /MD (or /MDd, for a debug build)compiler option, your program will link with MSVCRT.LIB (or MSVCRTD.LIB, for debug build), in addition to other libraries. In this case, your program will be dependent on MSVCRT.DLL (or MSVCRTD.DLL for debug build).

Case 2: Sample program test2.cpp


   // test2.cpp
   #include <iostream>
   void main()
   {
   }

If you build test.cpp using the /ML (or /MLd, for a debug build) compiler option, your program will link with LIBC.LIB (or LIBCD.LIB, for debug build) and LIBCP.LIB (or LIBCPD.LIB, for debug build), in addition to other libraries.

If you build test.cpp using the /MT (or /MTd, for a debug build) compiler option, your program will link with LIBCMT.LIB (or LIBCMTD.LIB, for debug build) and LIBCPMT.LIB (or LIBCPMTD.LIB, for debug build), in addition to other libraries.

If you build test.cpp using the /MD (or /MDd, for a debug build) compiler option, your program will link with MSVCRT.LIB (or MSVCRTD.LIB, for debug build) and MSVCPRT.LIB (or MSVCPRTD.LIB, for debug build), in addition to other libraries. For Visual C++ 6.0, your program will be dependent on MSVCRT.DLL and MSVCP60.DLL (or MSVCRTD.DLL and MSVCP60D.DLL for debug build). For Visual C++ 5.0, your program will be dependent on MSVCRT.DLL and MSVCP50.DLL (or MSVCRTD.DLL and MSVCP50D.DLL for debug build). For Visual C++ 4.2, your program will be dependent on MSVCRT.DLL (or MSVCRTD.DLL for debug build) and MSVCPRT.LIB (or MSVCPRTD.LIB, for debug build).

Case 3: Sample program test3.cpp


// test.cpp
#include <iostream.h>
void main()
{
}

If you build test.cpp using the /ML (or /MLd, for a debug build) compiler option, your program will link with LIBC.LIB (or LIBCD.LIB, for debug build) and LIBCI.LIB (or LIBCID.LIB, for debug build), in addition to other libraries.

If you build test.cpp using the /MT (or /MTd, for a debug build) compiler option, your program will link with LIBCMT.LIB (or LIBCMTD.LIB, for debug build) and LIBCIMT.LIB (or LIBCIMTD.LIB, for debug build), in addition to other libraries.

If you build test.cpp using the /MD (or /MDd, for a debug build) compiler option, your program will link with MSVCRT.LIB (or MSVCRTD.LIB, for debug build) and MSVCIRT.LIB (or MSVCIRTD.LIB, for debug build) in addition to other libraries. In this case, your program will be dependent on MSVCRT.DLL (or MSVCRTD.DLL for debug build) and MSVCIRT.DLL (or MSVCIRTD.DLL for debug build).

Headers determine whether the Standard C++ libraries, old iostream libraries, or neither will be linked. Compiler options (/ML[d], /MT[d], /MD[d]) determine which version of the libraries single-threaded, multithreaded, or multithreaded DLL is to be linked by default.

NOTE: It may seem that headers without the ".h" extension are Standard C++ headers and that headers with the ".h" extension are C Runtime headers or old iostream headers. This is not true. As explained below, the files <useoldio.h> and <use_ansi.h> determine the libraries your application will link with.

Actually, there are two header files, <useoldio.h> and <use_ansi.h>, that contain #pragmas. The #pragmas force either the old iostream library or the Standard C++ library to be linked in by default.

The header file <useoldio.h> contains #pragma statements, which force the old iostream library to be linked in. All old iostream headers include <useoldio.h>. So, if you include any old iostream header in your application, the old iostream library will be linked by default. The following table lists all the header files that include <useoldio.h>.


   Old iostream Headers
   --------------------

   FSTREAM.H   IOMANIP.H
   IOS.H       IOSTREAM.H
   ISTREAM.H   OSTREAM.H
   STDIOSTR.H  STREAMB.H
   STRSTREA.H

The header file <use_ansi.h> contains #pragma statements that force the Standard C++ Library to be linked in. All Standard C++ Headers include <use_ansi.h>. So if you include any Standard C++ header in your application, the Standard C++ library will be linked by default. The following table lists all the header files that include <use_ansi.h>.


   Standard C++ Headers
   ------------------------------------------------------

   ALGORITHM    BITSET     COMPLEX    DEQUE
   FSTREAM    FUNCTIONAL   IOMANIP    IOS
   IOSFWD      IOSTREAM    ISTREAM    ITERATOR
   LIMITS      LIST        LOCALE     MAP
   MEMORY      NUMERIC     OSTREAM    QUEUE
   SET         SSTREAM     STACK      STDEXCEPT
   STREAMBUF   STRING      STRSTREAM  TYPEINFO
   UTILITY     VALARRAY    VECTOR     XIOSBASE
   XLOCALE     XLOCINFO    XLOCMON    XLOCNUM
   XLOCTIME    XMEMORY     XSTRING    XTREE
   XUTILITY    YMATH.H

You cannot mix calls to the old iostream library and the new Standard C++ Library in Visual C++ 4.2.


                      Summary Table

------------------------------------------------------------------
| Compile   Old        New IOStream   Libraries                  |
| Option    IOStream   or STL         Linked With                |
|================================================================|
| /ML       No         No             LIBC.LIB                   |
|----------------------------------------------------------------|
| /MLd      No         No             LIBCD.LIB                  |
|----------------------------------------------------------------|
| /MT       No         No             LIBCMT.LIB                 |
|----------------------------------------------------------------|
| /MTd      No         No             LIBCMTD.LIB                |
|----------------------------------------------------------------|
| /MD       No         No             MSVCRT.LIB                 |
|----------------------------------------------------------------|
| /MDd      No         No             MSVCRTD.LIB                |
|----------------------------------------------------------------|
| /ML       No         Yes            LIBC.LIB,    LIBCP.LIB     |
|----------------------------------------------------------------|
| /MLd      No         Yes            LIBCD.LIB,   LIBCPD.LIB    |
|----------------------------------------------------------------|
| /MT       No         Yes            LIBCMT.LIB,  LIBCPMT.LIB   |
|----------------------------------------------------------------|
| /MTd      No         Yes            LIBCMTD.LIB, LIBCPMTD.LIB  |
|----------------------------------------------------------------|
| /MD       No         Yes            MSVCRT.LIB,  MSVCPRT.LIB   |
|----------------------------------------------------------------|
| /MDd      No         Yes            MSVCRTD.LIB, MSVCPRTD.LIB  |
|----------------------------------------------------------------|
| /ML       Yes        No             LIBC.LIB,    LIBCI.LIB     |
|----------------------------------------------------------------|
| /MLd      Yes        No             LIBCD.LIB,   LIBCID.LIB    |
|----------------------------------------------------------------|
| /MT       Yes        No             LIBCMT.LIB,  LIBCIMT.LIB   |
|----------------------------------------------------------------|
| /MTd      Yes        No             LIBCMTD.LIB, LIBCIMTD.LIB  |
|----------------------------------------------------------------|
| /MD       Yes        No             MSVCRT.LIB,  MSVCIRT.LIB   |
|----------------------------------------------------------------|
| /MDd      Yes        No             MSVCRTD.LIB, MSVCIRTD.LIB  |
------------------------------------------------------------------

          Summary Table for CRT DLLs Used
---------------------------------------------------
| Import Library   DLLs Used        DLLs Used     |
| Linked With      (VC 5.0|6.0)         (VC 4.2)  |
|=================================================|
| MSVCRT.LIB       MSVCRT.DLL       MSVCRT.DLL    |
|-------------------------------------------------|
| MSVCRTD.LIB      MSVCRTD.DLL      MSVCRTD.DLL   |
|-------------------------------------------------|
| MSVCPRT.LIB      MSVCP5(5|6)0.DLL               |
|-------------------------------------------------|
| MSVCPRTD.LIB     MSVCP5(5|6)0D.DLL              |
|-------------------------------------------------|
| MSVCIRT.LIB      MSVCIRT.DLL      MSVCIRT.DLL   |
|-------------------------------------------------|
| MSVCIRTD.LIB     MSVCIRTD.DLL     MSVCIRTD.DLL  |
---------------------------------------------------

REFERENCES

For additional information, please see the following article in the Microsoft Knowledge Base: For additional information about , please see the following article(s) in the Microsoft Knowledge Base:

Q154419 Standard C++ Library Frequently Asked Questions

Additional query words: MSVCRT.DLL MSVCIRT.DLL MSVCPRT.LIB LIBCI.LIB LIBCIMT.LIB LIBCP.LIB LIBCPMT.LIB

Keywords : kbCompiler kbGenInfo kbLangCPP kbVC420 kbVC500 kbVC600 LinkIss STLIss
Version : winnt:4.2,5.0
Platform : winnt
Issue type : kbinfo