vc143, detected vc142

what does it mean?
vc143, detected vc142

Found package configuration file:
1> [CMake] 
1> [CMake]     D:/TEST/boost/debug/lib/cmake/boost_system-1.78.0/boost_system-config.cmake
1> [CMake] 
1> [CMake]   but it set boost_system_FOUND to FALSE so package "boost_system" is
1> [CMake]   considered to be NOT FOUND.  Reason given by package:
1> [CMake] 
1> [CMake]   No suitable build variant has been found.
1> [CMake] 
1> [CMake]   The following variants have been tried and rejected:
1> [CMake] 
1> [CMake]   * boost_system-vc143-mt-gd-x64-1_78.lib (vc143, detected vc142, set
1> [CMake]   Boost_COMPILER to override)
1> [CMake] 
1> [CMake]   * libboost_system-vc143-mt-gd-x64-1_78.lib (vc143, detected vc142, set
1> [CMake]   Boost_COMPILER to override)
1> [CMake] 
1> [CMake]   * libboost_system-vc143-mt-sgd-x64-1_78.lib (vc143, detected vc142, set
1> [CMake]   Boost_COMPILER to override)
1> [CMake] 
1> [CMake] Call Stack (most recent call first)

It means that your Boost was compiled with a v143 toolchain, but you’re using a v142 toolchain. This combination is not supported. You’ll need to use the same compiler for Boost and your project.

what is the command to define vc142?
cmake -G generator?

It’s more about the toolchain than the generator. I think v142 is the default VS2019 toolchain.

v143 is vs2020 ?

VS2022; Visual Studio releases every 2-3 years.