CMake generated program fails to link on Windows: tries to link to non-existent file

I am trying to compile a very simple test program on Windows and keep getting linker errors. The program to link is the following:

#include <boost/asio/io_context.hpp>

int main()
{
    boost::asio::io_context context;
}

While the CMakeLists.txt looks like this:

cmake_minimum_required(VERSION 3.10 FATAL_ERROR)
project(windows-test)

SET(CMAKE_CXX_STANDARD 17)

find_package(Boost 1.6.7 COMPONENTS system)

include_directories("${Boost_INCLUDE_DIRS}")
add_executable(windows-test main.cpp)
target_link_libraries(windows-test Boost::system)

When building this using nmake, it fails with the following output:

-- Boost version: 1.67.0
-- Found the following Boost libraries:
--   system
-- Configuring done
-- Generating done
-- Build files have been written to: Z:/windows-test/build
[ 50%] Linking CXX executable windows-test.exe
LINK Pass 1: command "C:\PROGRA~2\MICROS~1\2017\BUILDT~1\VC\Tools\MSVC\1414~1.264\bin\Hostx64\x64\link.exe /nologo @CMakeFiles\windows-test.dir\objects1.rsp /out:windows-test.exe /implib:windows-test.lib /pdb:Z:\windows-test\build\windows-test.pdb /version:0.0 /machine:x64 /debug /INCREMENTAL /subsystem:console C:\local\boost_1_67_0\lib64-msvc-14.1\boost_system-vc141-mt-gd-x64-1_67.lib kernel32.lib user32.lib gdi32.lib winspool.lib shell32.lib ole32.lib oleaut32.lib uuid.lib comdlg32.lib advapi32.lib /MANIFEST /MANIFESTFILE:CMakeFiles\windows-test.dir/intermediate.manifest CMakeFiles\windows-test.dir/manifest.res" failed (exit code 1104) with the following output:
LINK : fatal error LNK1104: cannot open file 'libboost_system-vc141-mt-gd-x64-1_67.lib'
NMAKE : fatal error U1077: '"C:\Program Files\CMake\bin\cmake.exe"' : return code '0xffffffff'
Stop.
NMAKE : fatal error U1077: '"C:\Program Files (x86)\Microsoft Visual Studio\2017\BuildTools\VC\Tools\MSVC\14.14.26428\bin\HostX64\x64\nmake.exe"' : return code '0x2'
Stop.
NMAKE : fatal error U1077: '"C:\Program Files (x86)\Microsoft Visual Studio\2017\BuildTools\VC\Tools\MSVC\14.14.26428\bin\HostX64\x64\nmake.exe"' : return code '0x2'
Stop.

The file 'libboost_system-vc141-mt-gd-x64-1_67.lib' indeed does not exist on the system, but I don't know where it is coming from, since it does not appear on the linker command that it is executing. The linker command shows the file C:\local\boost_1_67_0\lib64-msvc-14.1\boost_system-vc141-mt-gd-x64-1_67.lib, which does exist.

Why oh why does it try to link to a missing file, that appears nowhere on the linker command? I feel way out of my depth here, since I haven't had to use Windows for almost 20 years and never before had to port to it.

Boost headers contain linker commands on Windows, so that Boost libraries are linked automatically when including the appropriate header. However, it seems your setup uses a different naming scheme for the libraries, which makes these fail to link.

You can disable the Boost auto-linking feature by defining the preprocessor macro BOOST_ALL_NO_LIB. Like this:

target_compile_definitions(windows-test PRIVATE BOOST_ALL_NO_LIB)