c++ - Visual studio 2015 run-time dependencies or how to get rid of Universal CRT?

Question

Compiled couple of .dll's using visual studio 2015, and tried to deploy on some older windows 7 / 64 bit. Tried also to guess which dll's are needed for application to start and copied MSVCP140.DLL & VCRUNTIME140.DLL - but application could not load vs2015 dll. Started to analyze what is wrong - and dependency walker showed dependencies from following dll's:

API-MS-WIN-CRT-MATH-L1-1-0.DLL
API-MS-WIN-CRT-HEAP-L1-1-0.DLL
API-MS-WIN-CRT-CONVERT-L1-1-0.DLL
API-MS-WIN-CRT-STRING-L1-1-0.DLL
API-MS-WIN-CRT-STDIO-L1-1-0.DLL
API-MS-WIN-CRT-RUNTIME-L1-1-0.DLL
API-MS-WIN-CRT-FILESYSTEM-L1-1-0.DLL
API-MS-WIN-CRT-TIME-L1-1-0.DLL

This was especially surprising since to my best understanding CRT is responsible for starting dll/exe, it does not provide any higher level services.

Ok, tried to figure out how to get rid of them or at least to minimize.

Found one article: https://blogs.msdn.microsoft.com/vcblog/2015/03/03/introducing-the-universal-crt/

It mentions about release static libraries - so I thought that I could link against them and get rid from *L1-1-0.DLL* dependency hell, but no matter what I have tried - I had no success. I've tried to link against libvcruntime.lib, libucrt.lib, libcmt.lib, tried to disable using linker option "/nodefaultlib:vcruntime.lib", and even tried to add include directory $(UniversalCRT_IncludePath), and also overriding some of define's as I have tried to guess they works - none of my attempts helped.

As an intermediate solution I've fall back to using Visual studio 2013, where CRT dll's are only two: msvcp120.dll, msvcr120.dll.

Of course you will probably recommend to install Visual studio 2015 run-times, but one of our requirement is to support standalone executable - which works without any installation - so additional installation is out of question for now.

Can you recommend me anything else than to wait Visual studio 2017 to arrive ?

Answer 1

I was able to solve this by setting the C/C++ > Code Generation > Runtime Library compiler option

• For Debug: from /MDd to /MTd
• For Release: from /MD to /MT

This removed all the API-MS-WIN-CRT-* and runtime dll references and caused all the CRT code to be statically linked.

Details on the new VS2015 Universal CRT (dynamic and static) are here: https://msdn.microsoft.com/en-us/library/abx4dbyh.aspx