RealView® Developer Kit Compiler and Libraries Guide 5.2.7. Thread-safety in the ARM C++ libraries

5.2.7. Thread-safety in the ARM C++ libraries

The following list summarizes thread-safety in the C++ libraries:

The function std::set_new_handler() is not thread-safe. This means that some forms of operator new and operator delete are not thread-safe with respect to std::set_new_handler():
- The default C++ runtime library implementations of the following use malloc() and free() and are thread-safe with respect to each other, malloc(), and free(). They are not thread-safe with respect to std::set_new_handler(). You are allowed to replace them.:
  ::operator new(std::size_t)
  ::operator new[](std::size_t)
  ::operator new(std::size_t, const std::nothrow_t&)
  ::operator new[](std::size_t, const std::nothrow_t)
  ::operator delete(void*)
  ::operator delete[](void*)
  ::operator delete(void*, const std::nothrow_t&)
  ::operator delete[](void*, const std::nothrow_t&)
- The following placement forms are also thread-safe. You are not allowed to replace them:
  ::operator new(std::size_t, void*)
  ::operator new[](std::size_t, void*)
  ::operator delete(void*, void*)
  ::operator delete[](void*, void*)
Construction and destruction of global objects is not thread-safe.
Construction of local static objects can be made thread-safe, if you re-implement the functions __cxa_guard_acquire(), __cxa_guard_release(), __cxa_guard_abort(), __cxa_atexit() and __aeabi_atexit() appropriately. For example, with appropriate re-implementing, the following construction of lsobj can be made thread-safe:
```
struct T { T(); };
void f() { static T lsobj; }
```
The __cxa_ and __aeabi_ functions are documented in the C++ ABI for the ARM Architecture specification.
Throwing an exception is thread-safe if any user constructors and destructors that get called, are also thread-safe. See the Exception Handling ABI for the ARM Architecture specification.
The ARM C++ library uses the ARM C library. To use the ARM C++ library in a multi-threaded environment, you must provide the functions described in Using the ARM C libraries with a multithreaded application.

Copyright © 2005 ARM Limited. All rights reserved.	ARM DUI 0282B
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