I dig into the wxPython’s source code, and I see that the error message comes from here:
wxPython-src-3.0.2.0/wxPython/src/osx_cocoa/_core.py
class App(wx.PyApp):
“”"
The wx.App class represents the application and is used to:
* bootstrap the wxPython system and initialize the underlying
gui toolkit
* set and get application-wide properties
* implement the windowing system main message or event loop,
and to dispatch events to window instances
* etc.
Every application must have a ``wx.App`` instance, and all
creation of UI objects should be delayed until after the
``wx.App`` object has been created in order to ensure that the gui
platform and wxWidgets have been fully initialized.
Normally you would derive from this class and implement an
``OnInit`` method that creates a frame and then calls
``self.SetTopWindow(frame)``.
"""
outputWindowClass = PyOnDemandOutputWindow
def __init__(self,
redirect=False,
filename=None,
useBestVisual=False,
clearSigInt=True):
"""
Construct a ``wx.App`` object.
:param redirect: Should ``sys.stdout`` and ``sys.stderr`` be
redirected? Defaults to False. If ``filename`` is None
then output will be redirected to a window that pops up
as needed. (You can control what kind of window is created
for the output by resetting the class variable
``outputWindowClass`` to a class of your choosing.)
:param filename: The name of a file to redirect output to, if
redirect is True.
:param useBestVisual: Should the app try to use the best
available visual provided by the system (only relevant on
systems that have more than one visual.) This parameter
must be used instead of calling `SetUseBestVisual` later
on because it must be set before the underlying GUI
toolkit is initialized.
:param clearSigInt: Should SIGINT be cleared? This allows the
app to terminate upon a Ctrl-C in the console like other
GUI apps will.
:note: You should override OnInit to do applicaition
initialization to ensure that the system, toolkit and
wxWidgets are fully initialized.
"""
wx.PyApp.__init__(self)
# make sure we can create a GUI
if not self.IsDisplayAvailable():
if wx.Platform == "__WXMAC__":
msg = """This program needs access to the screen.
Please run with a Framework build of python, and only when you are
logged in on the main display of your Mac."""
``
While, the actual test code was inside the file:
wxPython-src-3.0.2.0/wxPython/src/helpers.cpp
//----------------------------------------------------------------------
// Function to test if the Display (or whatever is the platform equivallent)
// can be connected to. This is accessable from wxPython as a staticmethod of
// wx.App called DisplayAvailable().
bool wxPyTestDisplayAvailable()
{
#ifdef WXGTK
Display* display;
display = XOpenDisplay(NULL);
if (display == NULL)
return false;
XCloseDisplay(display);
return true;
#endif
#ifdef WXMAC
// This is adapted from Python’s Mac/Modules/MacOS.c in the
// MacOS_WMAvailable function.
bool rv;
ProcessSerialNumber psn;
/*
** This is a fairly innocuous call to make if we don't have a window
** manager, or if we have no permission to talk to it. It will print
** a message on stderr, but at least it won't abort the process.
** It appears the function caches the result itself, and it's cheap, so
** no need for us to cache.
*/
#ifdef kCGNullDirectDisplay
/* On 10.1 CGMainDisplayID() isn’t available, and
** kCGNullDirectDisplay isn’t defined.
*/
if (CGMainDisplayID() == 0) {
rv = false;
} else
#endif
{
// Also foreground the application on the first call as a side-effect.
if (GetCurrentProcess(&psn) < 0 || SetFrontProcess(&psn) < 0) {
rv = false;
} else {
rv = true;
}
}
return rv;
#endif
#ifdef WXMSW
// TODO…
return true;
#endif
}
``
So, normally, we use the function named CGMainDisplayID, The document is here:Quartz Display Services Reference - [https://developer.apple.com/library/mac/documentation/GraphicsImaging/Reference/Quartz_Services_Ref/#//apple_ref/c/func/CGMainDisplayID](https://developer.apple.com/library/mac/documentation/GraphicsImaging/Reference/Quartz_Services_Ref/#//apple_ref/c/func/CGMainDisplayID)
I’m not sure, if GDB becomes an application bundle, it can return an valid CGDirectDisplayID ?`
`Thanks
Asmwarrior