Installing Clang for QDoc
QDoc uses Clang when parsing C++ files as well as function signatures in \fn commands. Clang is part of the LLVM Compiler Infrastructure Project. Therefore, if you are going to build QDoc from source, you need to install LLVM 6.0 or greater first. You can find the required pre-built binaries here.
To build QDoc on Debian-based Linux distributions, it is sufficient to install the
libclang-dev package and its dependencies. For running QDoc, the
libclang package is required.
Note: On Windows, after installing the pre-built LLVM you must restart your build shell to ensure that LLVM's binary directory is added to the PATH variable. This is needed to be able to run qdoc.
The Qt build system uses the tool
llvm-config to discover the location of LLVM on your system, and relies on the path to llvm-config being in the
PATH environment variable to do so.
llvm-config is commonly installed with LLVM and Clang on Linux systems, and also on macOS if LLVM is installed using Brew.
On Windows, the installation binaries provided by LLVM do not include
llvm-config. You may still have it on your system, if you have built LLVM yourself from source. If that is the case, and you want to let the build system find Clang automatically, add the path to
llvm-config to your
PATH environment variable. For example:
C:\> set PATH=%PATH%;C:\[build directory]\bin\Release"
Make sure to set the path to your LLVM build directory. The
llvm-config executable is located in
bin\Debug, reflecting the build version.
llvm-config is not in your
PATH environment variable, or not installed on your system, you can still build QDoc, by manually setting the environment variable
LLVM_INSTALL_DIR to point to the directory where the Clang libraries are installed. This directory should be the top level directory. For example, on a Linux or macOS system with LLVM installed to
$ export LLVM_INSTALL_DIR=/usr/llvm
Debian-based Linux distributions usually offer multiple versions of the
libclang packages, such as
libclang-<VERSION>. In this case,
LLVM_INSTALL_DIR should contain
On a Windows system with LLVM installed to
C:\> set LLVM_INSTALL_DIR=C:\Program Files\LLVM
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