error LNK2005: _sprintf already defined in ntdll.lib(ntdll.dll)

Question

I'm linking against ntdll.lib to use ZwQueryInformationProcess and am using the Multi-threaded runtime library.

ntdll seems to define some of the crt functions. So, when I link against it and also use the runtime library, I get linker errors.

Can I force the linker to use the crt functions and to ignore the ntdll symbols to get rid of the error? Or somehow else solve this error.

I know the documentation of ZwQueryInformationProcess suggests dynamic loading, but it's used in a static lib my main project is also linking to, and this has been working fine for a long time, so I'd prefer not to change it.

Thanks.

I've found a few discussions about this on other sites, eg: http://www.codeguru.com/forum/archive/index.php/t-414274.html but haven't seen anything that seems to provide a good solution. There are some mentions of changing the link order, but I can't see how to change the order in which the runtime library links via the project settings.

Answer 1

Changing the link order seems to solve it. To change the order of automatically linked libs, you need to ignore them by adding to "Ignore Specific Library" and then re-add them to "Additional Dependencies" in the order you want them linked. The error message was this:

1>libcmt.lib(wcstol.obj) : error LNK2005: _wcstoul already defined in ntdll.lib(ntdll.dll)

So, I added libcmt.lib as ignored, and also placed it at the start of the additional dependencies. This produced another error, which I followed with the same steps. So, the project properties ended up looking like this (ntdll.lib is at the end of the Additional Dependencies):

I also found adding /verbose:lib to the Linker -> Command Line -> Additional Options to be useful so that you can see exactly which libs are being linked and in what order.