Oliver,
Why is the minimally possible stack size in Boost.Context on Windows set to be 64k? This seems to be way too high for applications where only a minimal amount of stack is required. I assume, that since Boost.Context allocates the stack using VirtualAlloc the minimum possible value should be equal to the page size (see http://msdn.microsoft.com/en-us/library/windows/desktop/aa366887(v=vs. 85).as px).
boost.context provides a default implementation of a stack-allocator (class stack_allocator) which appends each stack a guard page (guard pages will not be mapped to physical pages - you don't was memory). Function VirtualProtect() is used to set the 'guard' flag on the page and requires VirtualAlloc().
I don't see how that info relates to my question, sorry. Even if I need only 4k of stack space (or 8k, or whatever), I still would like to get the guard page detecting stack overruns.
I decided to provide the same stacksize as Win32 Fiber API does - which is system's allocation granularity (64kB; using GetSystemInfo() ).
CreateFiberEx allows specifying committed and reserved stack sizes (http://msdn.microsoft.com/en-us/library/windows/desktop/ms682406(v=vs.85).a spx)
If context's default stack allocation does not satisfy your requirements you can easily implement and use your own stack allocator together with make_fcontext()/jump_fcontext().
I understand that I can implement my own allocator. But why should I be forced to do so if all I need to change is to remove the check for the minimal stack size. The constraint you're trying to enforce is something belonging into the documentation, not the code. The current implementation just makes your library less usable for people knowing what they're doing. BTW, on an unrelated note: I think the ctx::minimum_stacksize() and ctx::maximum_stacksize() functions should be tied to the allocator. They should not be global as they will return wrong numbers if a custom allocator is used. But that's just IMHO. Regards Hartmut --------------- http://boost-spirit.com http://stellar.cct.lsu.edu