https://invisible-island.net/xterm/xtoolkit/
XtGetApplicationNameAndClass - retrieve application name and class
#include <X11/Intrinsic.h>
void XtGetApplicationNameAndClass(Display* display, String* name_re-
turn, String* class_return);
display Specifies an open display connection that has been initial-
ized with XtDisplayInitialize.
name_return
Returns the application name.
class_return
Returns the application class.
XtGetApplicationNameAndClass returns the application name and class
passed to XtDisplayInitialize for the specified display. If the dis-
play was never initialized or has been closed, the result is undefined.
The returned strings are owned by the Intrinsics and must not be modi-
fied or freed by the caller.
XtDisplayInitialize(3)
X Toolkit Intrinsics - C Language Interface
Xlib - C Language X Interface
X Version 11 libXt 1.3.1 XtGetApplicationNameAndClass(3)