How do I fix LNK2019 errors after adding libpng to a VS2019 C++ project through Nuget?

Question

I am creating a solution that requires the use of libpng. I installed this library and its dependencies through Visual Studio 2019's Nuget Package Manager, and including <png.h> and using functions and macros from the library does not lead to errors. However, should I try building the solution, I get one LNK2019 error per every reference to the library function or variable. It seems to me that NuGet failed to add the library locations to the linker properties. I have found where are the.lib files located, but I'm lost as to which settings do I adjust so that the Studio looks for, and finds, these files in the NuGet directory.

Answer 1

The issue why the automatic nuget cannot add the lib dependencies into the Linker is that the c++ nuget is for v140 and v120 build tool. And if your project is created by VS2019 , VS uses v142 build tool(for VS2019 ) by default.

You can check the targets file(Methods to import lib automatically) from the nuget package <solution_folder>\packages\libpng.1.6.28.1\build\native\libpng.targets .

So this file cannot find V140 and V120 ,(your VS2019 uses V142 ) make the condition to false, so that auto import lib fails forever. That is the reason.

V140 is VC++2015 build tool while V120 is VC++ 2013 build tool .

If your PC has installed VS2015 and VS2013 , you can change build tool for VS0219 by right-click on the project Properties --> Configuration Properties --> General --> change Platfrom Toolset to Visual Studio 2015(v140).

For a better solution

And if your PC only has VS2019 and also for a better workaround,

You should install libpng-v142 nuget package instead and it is for VS2019 VC++ .