Zephyr C++ support documentation conflicts to the code

[evgeniy-paltsev]

Latest Zephyr documentation related to C++ support (doc/reference/kernel/other/cxx_support.rst) explicitly mentions that following features are not supported:

• Dynamic object management with the new and delete operators
• RTTI (runtime type information)
• Exceptions

However the commit 26e0f9a says that it

• Add support of C++ exceptions
• Add support of C++ RTTI
• Implements new and delete using k_malloc and k_free

which is conflicting to the documentation statements.

Hence the question to C++ experts:
Do we still have some significant flaws in these features implementation so we consider them as not supported or we just have outdated documentation?

[evgeniy-paltsev]

@nashif, @Benichou34 could you please take a look at this?
Thanks!

[nashif]

@evgeniy-paltsev yes, docs might be outdated, here is a list of what works and what does not: #31281

[github-actions]

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[github-actions]

This issue has been marked as stale because it has been open (more than) 60 days with no activity. Remove the stale label or add a comment saying that you would like to have the label removed otherwise this issue will automatically be closed in 14 days. Note, that you can always re-open a closed issue at any time.

[github-actions]

This issue has been marked as stale because it has been open (more than) 60 days with no activity. Remove the stale label or add a comment saying that you would like to have the label removed otherwise this issue will automatically be closed in 14 days. Note, that you can always re-open a closed issue at any time.

[github-actions]

This issue has been marked as stale because it has been open (more than) 60 days with no activity. Remove the stale label or add a comment saying that you would like to have the label removed otherwise this issue will automatically be closed in 14 days. Note, that you can always re-open a closed issue at any time.

[andygikling]

Bump, I think the very brief description of C++ support found in cxx_support.rst is misleading people (me).

First and foremost, there is evidence in other Github Issues that "new" does work. I've tried to compile a simple application to construct a new object from a main.cpp. Main.cpp compiles with g++ but then arm-zephyr-eabi/bin/ld.bfd tells me I have an undefined reference to "new" and the linking fails. Thoughts?

[andygikling]

Never mind I can confirm new is working. For people who end up looking here, you need to change a few things in your menuconfig:

CONFIG_CPLUSPLUS=y
# Enable 17
CONFIG_STD_CPP17=y
# Newlib 
CONFIG_NEWLIB_LIBC=y
# Standar c++ libraries
CONFIG_LIB_CPLUSPLUS=y
# Support runtime type system
CONFIG_RTTI=y

[stephanosio]

not stale

[stephanosio]

Related to #43636