Setting CMAKE_CXX_STANDARD leads to error

[chronoxor]

Setting CMAKE_CXX_STANDARD leads to error

Minimal CMakeLists.txt example reproducing bug or showing requested feature:

cmake_minimum_required(VERSION 3.0)

# Choose C++ standard
set(CMAKE_CXX_STANDARD 17)

list(APPEND CMAKE_MODULE_PATH ${CMAKE_SOURCE_DIR}/cmake/CMakePCHCompiler)

project(pchtest CXX CXXPCH)

add_library(engine src/engine.cpp src/library.cpp)
target_precompiled_header(engine src/prefix.h)

add_executable(demo src/demo.cpp)
target_link_libraries(demo engine)
target_precompiled_header(demo src/prefix.h REUSE engine)

Leads to error:

CMake Error at /home/user/workspace/CMakePCHCompiler/CMakePCHCompiler.cmake:116 (add_library):
  CXXPCH_STANDARD is set to invalid value '17'
Call Stack (most recent call first):
  CMakeLists.txt:10 (target_precompiled_header)

Additional information

• OS [Ubuntu]
• CMake version [3.14.1]
• Compiler type and version [GCC 7.2]

[m-7761]

There is code that deals with this in the module. I don't know if it neglects 17 exclusively or not off the top of my head. It may hardcode the version numbers. 17 may be newer than CMakePCHCompiler.