Class protected_stack_allocator

Boost.Coroutine provides the class protected_stack_allocator which models the stack-allocator concept. It appends a guard page at the end of each stack to protect against exceeding the stack. If the guard page is accessed (read or write operation) a segmentation fault/access violation is generated by the operating system.

	Important
	Using protected_stack_allocator is expensive. That is, launching a new coroutine with a new stack is expensive; the allocated stack is just as efficient to use as any other stack.

	Note
	The appended `guard page` is not mapped to physical memory, only virtual addresses are used.

#include <boost/coroutine/protected_stack_allocator.hpp>

template< typename traitsT >
struct basic_protected_stack_allocator
{
    typedef traitT  traits_type;

    void allocate( stack_context &, std::size_t size);

    void deallocate( stack_context &);
}

typedef basic_protected_stack_allocator< stack_traits > protected_stack_allocator

`void allocate( stack_context & sctx, std::size_t size)`

Preconditions:: traits_type::minimum_size() <= size and ! traits_type::is_unbounded() && ( traits_type::maximum_size() >= size).
Effects:: Allocates memory of at least size bytes and stores a pointer to the stack and its actual size in sctx. Depending on the architecture (the stack grows downwards/upwards) the stored address is the highest/lowest address of the stack.

`void deallocate( stack_context & sctx)`

Preconditions:: sctx.sp is valid, traits_type::minimum_size() <= sctx.size and ! traits_type::is_unbounded() && ( traits_type::maximum_size() >= sctx.size).
Effects:: Deallocates the stack space.

Boost C++ Libraries

Class protected_stack_allocator

void allocate( stack_context & sctx, std::size_t size)

void deallocate( stack_context & sctx)

`void allocate( stack_context & sctx, std::size_t size)`

`void deallocate( stack_context & sctx)`