What does the /DISALLOWLIB message mean in VC++ linker output?

Question

I'm in the process of tracking down a linker error with a VC++ 2005 application. When I switch on verbose linker output, I notice a ton of these messages:

Processed /DISALLOWLIB:nafxcwd.lib

What exactly does the /DISALLOWLIB switch mean?

Answer 1

It stops certain libraries from being used in conjunction with other libraries. For example, the msvcrtd.lib library has an entry disallowing msvcrt.lib (since putting the debug and release versions of that library in the same executable will cause all sorts of problems).

I'm not sure it's actually a linker switch, though I've never tried it (it's not documented as such in any of the linker versions from the various Visual Studio releases). It is possible to insert:

#pragma comment(linker, "/disallowlib:somelib.lib")

in your source files so it's possible the linker may allow it as well. Where you do find it is within the libraries. If you execute:

dumpbin.exe /rawdata msvcrtd.lib

you'll see something like:

/disallowlib:libcmt.lib
/disallowlib:libcmtd.lib
/disallowlib:msvcrt.lib

in the output, meaning that the "command" is part of the library contents itself.