gistfile1.cpp

#include <ucontext.h>
#include <iostream>

using namespace std;

ucontext_t retctx;

std::size_t ssize = 1024 * 64;
char* stack = new char[ssize];

extern "C" {
  int quux(int i)
  {
    cout << "quux" << i << endl;
    return 1;
  }
}

class Foo
{
public:

  static void foo()
  {
    cout << "foo->" << endl;
    int ret = quux(5);
    cout << ret << endl << "<-foo" << endl;
    setcontext(&retctx);
    return;
  }

  static void bar() { cout << "bar" << endl; }
};

int caller()
{
  bool again = true;

  getcontext(&retctx);

  if (!again)
    return 1;

  again = false;

  ucontext_t ctx;
  getcontext(&ctx);

  ctx.uc_link = NULL;
  ctx.uc_stack.ss_sp = stack;
  ctx.uc_stack.ss_size = ssize;
  ctx.uc_stack.ss_flags = 0;

  makecontext(&ctx, &Foo::foo, 0);
  setcontext(&ctx);
}

int main(int c, char** v)
{
//  bool again = true;
//
//  getcontext(&retctx);
//
//  if (!again) {
//    delete [] stack;
//    Foo::bar();
//
//    cout << "end" << endl;
//    return 0;
//  }
//
//  again = false;
  int i = caller();
  return 0;
}