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CMake can't find protobuf when compiling Google's protobuf example

I am trying to solve this problem for 2 days now with no luck. I've read an endless number of threads allover the web and tried a lot of suggestions but so far with no luck.

I'm doing this on Windows 10 with VS2017 and most recent VS Code installed. I installed protobuf with vcpkg install protobuf:

The package protobuf:x64-windows provides CMake targets:

find_package(protobuf CONFIG REQUIRED)
target_link_libraries(main PRIVATE protobuf::libprotoc protobuf::libprotobuf protobuf::libprotobuf-lite)

I downloaded Google's example code and extracted it on my drive. The .PROTO file compiles without a problem:

d:\protobuf-3.12.2\examples>protoc -I=d:\protobuf-3.12.2\examples --cpp_out=d:\protobuf-3.12.2\examples d:\protobuf-3.12.2\examples\addressbook.proto

and creates the two files "addressbook.pb.cc" and "addressbook.pb.h" as expected.

Now when I try to compile the project in Visual Studio Code it constantly fails no matter how I modify the CMakeLists.txt file. As mentioned I went through dozens of threads regarding this problem and tried a lot with no luck.

Update 29.05.2020

I checked that protobuf is installed just once and indeed the demo package also included a full protobuf installation. I removed this extra demo package and un-/installed protobuf with vcpkg. I then compiled the .proto file with protoc (which is in my path) and got the two files "addressbook.pb.cc" and "addressbook.pb.h".

Then I tried to compile the project again, this time using the CMakeLists.txt that came with the demo.

The relevant part seems to be right in the beginning:

# Minimum CMake required
cmake_minimum_required(VERSION 2.8.12)
# Project
project(protobuf-examples)
# Find required protobuf package
find_package(protobuf CONFIG REQUIRED)
if(protobuf_VERBOSE)
  message(STATUS "Using Protocol Buffers ${Protobuf_VERSION}")
endif()
set(CMAKE_INCLUDE_CURRENT_DIR TRUE)

Compiling this gives me:

[main] Building folder: examples 
[main] Configuring folder: examples 
[cms-client] Configuring using the "Visual Studio 15 2017" CMake generator with platform "x64" and toolset "host=x64"
[cmake] Selecting Windows SDK version 10.0.17763.0 to target Windows 
...
[cmake] CMake Error at CMakeLists.txt:8 (find_package):
[cmake]   Could not find a package configuration file provided by "protobuf" with any
[cmake]   of the following names:
[cmake] 
[cmake]     protobufConfig.cmake
[cmake]     protobuf-config.cmake
[cmake] 
[cmake]   Add the installation prefix of "protobuf" to CMAKE_PREFIX_PATH or set
[cmake]   "protobuf_DIR" to a directory containing one of the above files.  If
[cmake]   "protobuf" provides a separate development package or SDK, be sure it has
[cmake]   been installed.
[cmake] 
[cmake] 
[cmake] Configuring incomplete, errors occurred!
[cmake] See also "d:/vcpkg/buildtrees/protobuf/src/v3.12.0-8ba83cbbdb/examples/build/CMakeFiles/CMakeOutput.log".
[cms-driver] Error during CMake configure: [cmake-server] Configuration failed.

The file protobuf-config.cmake can be found multiple times in the protobuf folder:

  • D:\vcpkg\buildtrees\protobuf\<BUILDCFG>\share\protobuf\protobuf-config.cmake
  • D:\vcpkg\installed\<BUILDCFG>\share\protobuf\protobuf-config.cmake
  • D:\vcpkg\packages\<BUILDCFG>\share\protobuf\protobuf-config.cmake

What could be the cause that CMake can't locate these files?

Solution

  • Fair warning I am no expert.

    I ran in to a similar problem in my own build trying to get Boost working and I think it has to do with your environment variables and how you have your Visual Studio setup. While you are setting crucial things such as

    SET(PROTOBUF_INCLUDE_DIR "d:/vcpkg/packages/protobuf_x64-windows/include/")

    The actual find_package(protobuf CONFIG REQUIRED) throws these settings out the window. Once it finds that config file it only cares about what the config file is finding, I think this is the cause of how your first MESSAGE has the right one, and then your 2nd one doesn't find one.

    Are you positive you only have one installation of protobuf on your machine?

    • It appears to be finding this "used as include directory in directory D:/protobuf-3.12.2/examples"
    • yet you are trying to find "D:/vcpkg/packages/protobuf_x64-windows" no?

    Try adding a "-DCMAKE_PREFIX_PATH="d:/vcpkg/packages/protobuf_x64-windows" to your CMake options in Visual Studio

    Good luck and sorry if this doesn't help, I'm relatively new to programming but its worth a try.