XtGetClassExtension - locate a class extension record
#include <X11/Intrinsic.h>
XtPointer XtGetClassExtension(WidgetClass object_class,
    Cardinal byte_offset, XrmQuark type, long version,
    Cardinal record_size);
  - object_class
- Specifies the widget class containing the extension list to be
    searched.
- byte_offset
- Specifies the offset in bytes form the base of the widget class of the
      extension field to be searched.
- type
- Specifies the name of the class extension to be located.
- version
- Specifies the minimum acceptable version of the class extension required
      for a match.
- record_size
- Specifies the minimum acceptable length of the class extension record
      required for match, or 0.
The list of extension records at the specified offset in the specified
  widget_class will be searched for a match on the specified type,
  a version greater than or equal to the specified version, and a record
  size greater than or equal the specified record_size if it is nonzero.
  XtGetClassExtension returns a pointer to a matching extension record or
  NULL if no match is found. The returned extension record is owned by the
  widget class and must not be modified or freed by the caller, except possibly
  to be modified by the widget class owner.
X Toolkit Intrinsics - C Language Interface
Xlib - C Language X Interface