**Important:** This does not mean *yet* that C++11 features should be used
in contributions to Godot's codebase.
For now this change is done solely for feature branches working on Vulkan
support and GDScript typed instruction sets for Godot 4.0, which will both
use C++11 features and are based on the master branch.
The plan is to start porting the codebase to C++11 after Godot 3.2 is
released, following upcoming guidelines on the subset of new features that
should be used, and when/how to use them.
We will advertise clearly when C++11 contributions are open, especially
once we start a coordinated effort to port Godot's massive codebase. In the
meantime, please bear with us and good ol' C++03. :)
It's the recommended way to set those, and is more portable
(automatically prepends -D for GCC/Clang and /D for MSVC).
We still use CPPFLAGS for some pre-processor flags which are not
defines.
Include paths are processed from left to right, so we use Prepend to
ensure that paths to bundled thirdparty files will have precedence over
system paths (e.g. `/usr/include` should have lowest priority).
Many contributors (me included) did not fully understand what CCFLAGS,
CXXFLAGS and CPPFLAGS refer to exactly, and were thus not using them
in the way they are intended to be.
As per the SCons manual: https://www.scons.org/doc/HTML/scons-user/apa.html
- CCFLAGS: General options that are passed to the C and C++ compilers.
- CFLAGS: General options that are passed to the C compiler (C only;
not C++).
- CXXFLAGS: General options that are passed to the C++ compiler. By
default, this includes the value of $CCFLAGS, so that setting
$CCFLAGS affects both C and C++ compilation.
- CPPFLAGS: User-specified C preprocessor options. These will be
included in any command that uses the C preprocessor, including not
just compilation of C and C++ source files [...], but also [...]
Fortran [...] and [...] assembly language source file[s].
TL;DR: Compiler options go to CCFLAGS, unless they must be restricted
to either C (CFLAGS) or C++ (CXXFLAGS). Preprocessor defines go to
CPPFLAGS.
Rémi Verschelde
Windy Darian
Juan Linietsky