how to avoid "already defined error" in C++

c++ linker visual-studio-6
Mantichora picture Mantichora · Jun 24, 2009 · Viewed 12k times · Source

I am gettings these type of errors in a MFC VS6 project while linking the application:

msvcrt.lib(MSVCRT.dll) : error LNK2005: _atoi already defined in LIBC.lib(atox.obj)

I know what it means (a function exists in 2 different libraries); to solve it I should have to exclude one of the 2 libraries (msvcrt.lib or libc.lib).

But if I do this there are all kinds of unresolved external errors. So I would like to keep using both libraries.

Is there any way to tell the linker that I want to use the _atoi function in libc.lib and not in msvcrt.lib (or the other way around)?

Any help or direction would be great.

Answer

fbonnet picture fbonnet · Jun 24, 2009

This error certainly means that you're linking two pieces of codes that have been compiled using distinct runtime libraries. MSVCRT.dll is the dynamic version, while LIBC.lib is the static one. If you do this, all hell break loose. Try finding which parts of your code use which version, and sort this out.

Related questions

Linker: cannot open file 'nafxcwd.lib'

I have problem with compiling my project via visual studio 2013. I got this linker error: LINK : fatal error LNK1104: cannot open file 'nafxcwd.lib' According to this page, I must use MFC in shared library. But I don't use MFC …

Read More
error LNK2019: unresolved external symbol _main referenced in function ___tmainCRTStartup

I don't know what's wrong with it.. I can't find where the error is, commenting out the implementation doesn't resolve the error either. Header File #ifndef MAIN_SAVITCH_SEQUENCE_H #define MAIN_SAVITCH_SEQUENCE_H #include <cstdlib> // Provides …

Read More
How to specify preference of library path?

I'm compiling a c++ program using g++ and ld. I have a .so library I want to be used during linking. However, a library of the same name exists in /usr/local/lib, and ld is choosing that library over …

Read More