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Boost.Coroutine2 supports usage of a segmented_stack, e. g. the size of the stack grows on demand. The coroutine is created with a minimal stack size and will be increased as required. Class segmented_stack models the stack-allocator concept. In contrast to protected_fixedsize_stack and fixedsize_stack it creates a stack which grows on demand.
| ![[Note]](../../../../../../doc/src/images/note.png) | Note | 
|---|---|
| 
          Segmented stacks are currently only supported by gcc
          from version 4.7 clang
          from version 3.4 onwards. In order to
          use a segmented-stack Boost.Context
          must be built with property  | 
#include <boost/coroutine2/segmented_stack.hpp> struct segmented_stack { segmented_stack(std::size_t size = traits_type::default_size()); stack_context allocate(); void deallocate( stack_context &); }
stack_context allocate()
      
              traits_type::minimum:size()
              <= size
              and ! traits_type::is_unbounded() &&
              ( traits_type::maximum:size() >= size).
            
              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)
      
              sctx.sp is valid, traits_type::minimum:size() <= sctx.size and !
              traits_type::is_unbounded()
              && (
              traits_type::maximum:size()
              >= sctx.size).
            
Deallocates the stack space.
| ![[Note]](../../../../../../doc/src/images/note.png) | Note | 
|---|---|
| If the library is compiled for segmented stacks, segmented-stack is the only available stack allocator. |