DOKK / manpages / debian 10 / libxt-dev / XtGetDisplays.3.en
XtGetDisplays(3) XT FUNCTIONS XtGetDisplays(3)

XtGetDisplays - retrieve a list of displays associated with an application context

void XtGetDisplays(XtAppContext app_context, Display ***dpy_return, Cardinal* num_dpy_return);

Specifies the application context.
Returns a list of open X display connections in the specified application context.
Returns the count of open X display connections in dpy_return.

To free the list of displays, use XtFree.

X Toolkit Intrinsics - C Language Interface
Xlib - C Language X Interface

libXt 1.1.5 X Version 11