C / C++ / MFC

class coroutine {
public:
	void (*action1)(int);
	Stack local_stack;
	coroutine(void (*action)(int ), int id); ///< will create coroutine
	~coroutine();
	static void yield();
	};

coroutine *global_coro;
fcontext_t context_array[2];
coroutine :: coroutine(void (*action)(int), int id)
			{
			global_coro=this;
			action1=action;
			fcontext_t f_ctx = make_fcontext(global_coro->local_stack.local_stack, 1000, global_coro->action1);//Save the current context of coroutine for the sake of making switch context.
// make_fcontext is in .S file taken from boost::context
			context_array[0]=f_ctx; // Global Array to store the coroutine context so that i can switch the context
			}

coroutine::~coroutine(){}

void coroutine::yield(){

transfer_t tr = jump_fcontext(context_of_current_corotine, context_of_next_coroutine ); //Also in .S file 

extern MemoryPool memPoolObj;

class Stack {
public:
	void *local_stack;
	MemoryPool& m_memPool=memPoolObj;
	Stack();
	~Stack();
};

#include "Stack.h"
MemoryPool memPoolObj;
Stack::Stack() {
	auto *local_stack= m_memPool.Allocate();
}
Stack::~Stack() {}

typedef void*   fcontext_t;

struct transfer_t
{
    fcontext_t  fctx;
    void    *   data;
};

extern "C"
transfer_t jump_fcontext( fcontext_t const to, void * vp);
extern "C"
fcontext_t make_fcontext( void * sp, std::size_t size, void (* fn)( int) );

#include "coroutine.h"
void workPackage(int id){
	printf("Coroutine with id %d is called\n", id);
	coroutine::yield();
	printf("Coroutine with id %d is resumed after first yield\n", id);
	coroutine::yield();
	printf("Coroutine with id %d is resumed after second yield\n", id);
}



int main() {
	coroutine Coro1(workPackage, 1);
	coroutine Coro2(workPackage, 2);
	printf("Main is finished \n");
}

Use of uninitialised value of size 8
==24145==    at 0x10922B: make_fcontext (in /home/user1/eclipse-workspace/coroutines/Debug/coroutines)
==24145==    by 0x10912D: main (main.cpp:32)
==24145== 
==24145== (action on error) vgdb me ... 
==24145== Continuing ...
==24145== Invalid write of size 8
==24145==    at 0x10922B: make_fcontext (in /home/user1/eclipse-workspace/coroutines/Debug/coroutines)
==24145==    by 0x10912D: main (main.cpp:32)
==24145==  Address 0xffffffffffffffe8 is not stack'd, malloc'd or (recently) free'd