error: no type named 'invoke_result_t' in namespace 'std' gcc-7

Question

My cmake file:

cmake_minimum_required(VERSION 3.10)
set(CMAKE_CXX_COMPILER "gcc-7")


project(invertedindex)

set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wextra -Wconversion -O0")

set(SOURCE_FILES main.cpp inverted_index.hpp params.hpp)
add_executable(invertedindex ${SOURCE_FILES})

Fortunately I looked at the generated compiler command

/usr/local/bin/gcc-7    -Wall -Wextra -Wconversion -O0   -std=gnu++1z -o CMakeFiles/invertedindex.dir/main.cpp.o -c /Users/adam/school/cpp/invertedindex/main.cpp

and saw -std=gnu++1z . I have no interest in studying long hours what the f*ck that is and why it is there when I have

set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

It suspect that -std=gnu++1z is not a stable, finished library, or sth. But gcc 7 supports most of the features of c++17 standard.

when I chickened out of knowing that it should work, I replaced manually the generated command parameter to -std=gnu++17 and it worked. What's wrong? How do I make it work in cmake?

Answer 1

See how to specify compiler in cmake I was using the third method which is marked with avoid. First method, that is setting CXX env var didn't work (compiler was some Mac g++). So I tried the second method - specifying compiler in cmake args -D CMAKE_C_COMPILER=gcc-7 , which worked. Even though generating again c++1z param. I don't understand it, but until I breaks I'm good.

/usr/local/bin/gcc-7    -Wall -Wextra -Wconversion -O0 -g   -std=gnu++1z -o CMakeFiles/invertedindex.dir/main.cpp.o -c /Users/adam/school/cpp/invertedindex/main.cpp