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Tools and versions: Visual Sudio 2017, Google Protobufs 3.11.3, gRPC 1.27.1, vcpkg 2020.02.04, on Microsoft Windows

I used vcpkg to build the Windows native C++ versions of gRPC and protobuf (and other dependencies) for Windows (x86). Everything builds successfully.

When I build my application I include "libprotobuf.lib" as a linker input. However, it doesn't get linked. Instead, my program will only run if the "libprotobuf.dll" is present for the program to load. I don't know of another way to specify that the library should be statically linked.

During the build of my application, I see a lot of warnings like this: include\google\protobuf\duration.pb.h(220): warning C4251: 'google::protobuf::Duration::_internal_metadata_': class 'google::protobuf::internal::InternalMetadataWithArena' needs to have dll-interface to be used by clients of class 'google::protobuf::Duration'

This page mentions the warnings and says that static linking is the default but it seems like vcpkg isn't building it that way or I need to reference the library a different way.

I've also seen this page that offers a solution. That helped a bit. It made Visual Studio recognize unresolved externals, so at least it was trying to statically link the .lib file(s). With that in place I've tried various combinations of .lib files for protobuf, grpc, and dependencies but I still can't get a successful build - and the compiler warnings are still generated.

I feel like I'm missing something (a pre-processor define maybe) during the vcpkg build that would build the headers or libraries differently. I've tried to change some of the build settings but they're always overwritten when vcpkg generates cmake files for the build.

Or I'm missing the right combination of library files to reference from my project.

Has anyone gotten this to work? If you have examples of building the libraries for static linking via vcpkg, or the correct way to link the libraries in VS2017 project, could you share your information?

Ken
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1 Answers1

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Finally got a chance to come back to this. The problem came down to two things: 1. Realizing that you can specify a triplet (as noted in original question). 2. Finally realizing using the static libraries also meant I had to switch my application to static c runtime libraries instead of shared dlls.

I can't switch my application. I've done testing with this non-static mode operation though. I haven't seen any problems, but does anyone else use protobufs (and gRPC this way) - it doesn't appear to be recommended.

Ken
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