Use following instructions to install IWYU (https://include-what-you-use.org/) on Ubuntu 18.04.3 LTS:
sudo apt-get update
sudo apt-get install -y build-essential cmake git zlib1g-dev libncurses5-dev llvm-6.0-dev libclang-6.0-dev libclang-6.0-dev clang-6.0
git clone https://github.com/include-what-you-use/include-what-you-use.git iwyu.git
git checkout clang_6.0
mkdir -p build
cmake -DIWYU_LLVM_ROOT_PATH=/usr/lib/llvm-6.0 ..
Once installation is complete, you will find `include-what-you-need`
# include-what-you-use --version
include-what-you-use 0.10 (git:a1878c4) based on clang version 6.0.0-1ubuntu2 (tags/RELEASE_600/final)
Build your cpp project with cmake and pass on an extra parameter
-DCMAKE_EXPORT_COMPILE_COMMANDS=TRUE to cmake. It will produce `compile_commands.json` file in your build folder for the project.
iwyu_tool.py -p </path/to/folder/having/compile_command.json>. It may take time depending upon the code size.
fix_includes can be used to apply recommended changes.
To use it in VSCode add following to the
"label": "Run iwyu",
Use following commands if you want to see default macros passed by the compiler during compilation:
# Compiler default macros in standard build
gcc -dM -E - < /dev/null
# Compiler default macros with optimization level 0
gcc -dM -E -O0 - < /dev/null
# Compiler list warning enabled using following flags
gcc -Wall -Wextra -Q --help=warning
# Compiler default macros in case of c++11
g++ -dM -E -x c++ -std=c++11 - < /dev/null
C++11 supports Thread library (http://en.cppreference.com/w/cpp/thread). If you are using it in your application you have to pass -pthread to g++ linker to inform it which sort of backend should be used for linking Thread library. If -pthread is not passed your application will end up with following execution error:
terminate called after throwing an instance of 'std::system_error'
what(): Enable multithreading to use std::thread: Operation not permitted
Aborted (core dumped)
I was playing with c++11/14 in a project created using Qt Creator. I found that Qt creator is passing -std=gnu++0x to compiler whereas my .pro file was configured to use c++11.
My <qt_project>.pro file was having:
CONFIG += c++11
The fix for this problem was to force Qt creator to use specified c++ standard instead of using default one. This can be done by having strict_c++ keyword in .pro file.
CONFIG += strict_c++ c++11