/*
 * This program demostrates a threading problem with FLTK on MinGW and
 * MSYS.  The main thread should be able to process events from
 * windows shown in another thread, but in order to make this work on
 * MinGW, one must enable a hack.  The hack causes the latest thread
 * that creates a window to take over event processing, since if it is
 * left to the main thread, the new windows remains invisible.
 *
 * The problem behavior has been observed on Windows XP, with MinGW
 * 3.1.0, MSYS 1.0.10, and FLTK 1.1.6.
 *
 * John D. Ramsdell -- January 2005
 */

#define ENABLE_HACK

#include <FL/Fl.H>
#include <FL/Fl_Window.H>
#include <FL/Fl_Button.H>

#if defined HAVE_PTHREAD_H
#  include <errno.h>
#  include <pthread.h>
#  define thread_exit() return 0

typedef pthread_t thread_t;
typedef void *result_t;

int thread_create(thread_t *t, void *(*f)(void *), void *p)
{
  int i;
  pthread_attr_t a[1];
  if (pthread_attr_init(a))
    return EINVAL;
  if (pthread_attr_setdetachstate(a, PTHREAD_CREATE_DETACHED))
    return EINVAL;
  i = pthread_create(t, a, f, p);
  if (pthread_attr_destroy(a))
    return EINVAL;
  return i;
}
#elif defined WIN32
#  include <errno.h>
#  include <windows.h>
#  include <process.h>
#  define thread_exit() return

typedef unsigned long thread_t;
#define result_t void __cdecl

int thread_create(thread_t *t, void (__cdecl *f)(void *), void *p)
{
  *t = _beginthread(f, 0, p);
  if (*t != (thread_t)-1)
    return 0;
  else
    return errno;
}
#else
#error "No thread package available"
#endif

Fl_Window *mkwin();

result_t run(void *data)
{
  Fl::lock();
  Fl_Window *window = mkwin();
  window->show();
#if defined ENABLE_HACK
  Fl::run();
#endif
  Fl::awake();
  Fl::unlock();
  thread_exit();
}

void run_callback(Fl_Widget *w, void *d)
{
  thread_t t;
  thread_create(&t, run, 0);
}

int main(int argc, char **argv)
{
  Fl::lock();
  Fl_Window *window = mkwin();
  window->show(argc, argv);
  return Fl::run();
}

Fl_Window *mkwin()
{
  Fl_Window *window = new Fl_Window(300,180);
  Fl_Button *button = new Fl_Button(20,40,260,100,"Spawn Thread");
  button->box(FL_UP_BOX);
  button->labelsize(36);
  button->labelfont(FL_BOLD+FL_ITALIC);
  button->labeltype(FL_SHADOW_LABEL);
  button->callback(run_callback, window);
  window->end();
  return window;
}