Please make sure that this is a bug. As per our
GitHub Policy,
we only address code/doc bugs, performance issues, feature requests and
build/installation issues on GitHub. tag:bug_template

System information

• Have I written custom code (as opposed to using a stock
  example script provided in TensorFlow): Yes

(e.g. for links and images), because some of these examples are now being rendered in the docs.

Added by @fchollet in requests for contributions.

🐛 Bug

Compiling against the C++ API on macOS using GCC-9.3, and cmake seems to use a bad flag:
... -fopenmp -D_GLIBCXX_USE_CXX11_ABI= -std=c++14 ... -- note how it "blanks out" the _GLIBCXX_USE_CXX11_ABI variable. This causes the compiler to fail in the stdlib:

/usr/local/Cellar/gcc@9/9.3.0/include/c++/9.3.0/x86_64-apple-darwin18/bits/c++config.h:273:27: error: #if with no expr

Describe the issue linked to the documentation

Follows from #17387

Suggest a potential alternative/fix

Stop referencing preprocessing functions e.g. :

maxabs_scale
minmax_scale
normalize
quantile_transform
robust_scale
scale
power_transform

in the UG, and only add them e.g. in the "See Also" sections, or even just in the API ref.

In particular right now the first entr

Currently, the docs for the Printf standardlib simply mentions it uses "C printf style format specification", but does not specify what that is, nor provides a link to the C printf format.

It would be nice to explain it in the docs.

It would be great to have a tutorial for using the C API of XGBoost in a C or C++ application. Some important components:

• How to configure the CMakeLists.txt of your application to link with XGBoost (either statically or dynamically)
• How to install XGBoost library into a system prefix or a Conda environment.
• Useful tips, such as remembering to clean up allocated XGBoost object handles, or