libs/libxx/README.txt
^^^^^^^^^^^^^^^^^^^^^
This directory contains three C++ library:
- A fragmentary C++ library that will allow to build only the simplest of
C++ applications. In the deeply embedded world, that is probably all
that is necessary.
At present, only the following are supported here:
- void *operator new(std::size_t nbytes);
- void operator delete(void* ptr);
- void operator delete[](void *ptr);
- void __cxa_pure_virtual(void);
- int __aeabi_atexit(void* object, void (*destroyer)(void*),
void *dso_handle);
- int __cxa_atexit(__cxa_exitfunc_t func, FAR void *arg,
FAR void *dso_handle);
This implementation is selected when neither of the following
two options are enabled.
- LLVM "libc++" C++ library (http://libcxx.llvm.org/)
This implementation is selected with CONFIG_LIBCXX=y.
- uClibc++ C++ library (http://cxx.uclibc.org/)
This implementation is selected with CONFIG_UCLIBCXX=y.
operator new
------------
This operator should take a type of size_t. But size_t has an unknown underlying
type. In the nuttx sys/types.h header file, size_t is typed as uint32_t
(which is determined by architecture-specific logic). But the C++
compiler may believe that size_t is of a different type resulting in
compilation errors in the operator. Using the underlying integer type
instead of size_t seems to resolve the compilation issues. Need to
REVISIT this.
Once some C++ compilers, this will cause an error:
Problem: "'operator new' takes size_t ('...') as first parameter"
Workaround: Add -fpermissive to the compilation flags
4ae7f4c1f6