Some algorithms, such as stable_sort and inplace_merge, are adaptive: they attempt to use extra temporary memory to store intermediate results, and their run-time complexity is better if that extra memory is available. These algorithms use temporary_buffer to allocate that extra memory.

temporary_buffer's constructor takes two arguments, first and last, of type ForwardIterator; the constructor allocates a buffer that is large enough to contain N objects of type T, where 0 <= N <= last – first [1], and it fills the buffer with objects of type T. The member functions begin() and end() return iterators that point to the beginning and the end of the buffer.

Note that the elements in the buffer are guaranteed to be initialized; that is, begin() points to an object of type T, not to raw memory. However, the initial values of the buffer's elements are unspecified. You should not rely on them to be initialized to any particular value.

temporary_buffer does not have a copy constructor, or an assignment operator. Those operations would have complicated, and not terribly useful, semantics.

(Earlier versions of the STL used get_temporary_buffer and return_temporary_buffer instead of temporary_buffer. temporary_buffer is more convenient, because it does not require using uninitialized_copy , and in some cases it is also more efficient. Additionally, it is much easier to write exception-safe code with temporary_buffer than with get_temporary_buffer and return_temporary_buffer.)