tk_setclassprocs(3)
NAME
Tk_SetClassProcs - register widget specific procedures
SYNOPSIS
#include <tk.h> Tk_SetClassProcs(tkwin, procs, instanceData)
ARGUMENTS
- Tk_Window tkwin (in) Token for window
- to modify.
- Tk_ClassProcs *procs (in) Pointer to data
- structure contain
ing widget spe
cific procedures.
The data structure
pointed to by
procs must be
static: Tk keeps a
reference to it as
long as the window
exists. - ClientData instanceData (in) Arbitrary one-word
- value to pass to
widget callbacks.
DESCRIPTION
Tk_SetClassProcs is called to register a set of procedures
that are used as callbacks in different places.
- The structure pointed to by procs contains the following:
- typedef struct Tk_ClassProcs {
unsigned int size;
Tk_ClassWorldChangedProc *worldChangedProc;
Tk_ClassCreateProc *createProc;
Tk_ClassModalProc *modalProc; - } Tk_ClassProcs;
- The size field is used to simplify future expansion of the
structure. It should always be set to (literally)
sizeof(Tk_ClassProcs). - worldChangedProc is invoked when the system has altered in
some way that requires some reaction from the widget. For
example, when a font alias (see the font manual entry) is
reconfigured, widgets configured to use that font alias
must update their display accordingly. worldChangedProc should have arguments and results that match the type
Tk_ClassWorldChangedProc: - typedef void Tk_ClassWorldChangedProc(
ClientData instanceData);
- The instanceData parameter passed to the worldChangedProc will be identical to the instanceData paramter passed to Tk_SetClassProcs.
- createProc is used to create platform-dependant windows.
It is invoked by Tk_MakeWindowExist. createProc should
have arguments and results that match the type Tk_Class
CreateProc:
typedef Window Tk_ClassCreateProc(Tk_Window tkwin,
Window parent,
ClientData instanceData);The tkwin and instanceData parameters will be identical to the tkwin and instanceData parameters passed to Tk_Set ClassProcs. The parent parameter will be the parent of the window to be created. The createProc should return the created window.modalProc is invoked after all bindings on a widget have been triggered in order to handle a modal loop. modalProc should have arguments and results that match the type
Tk_ClassModalProc:typedef void Tk_ClassModalProc(Tk_Window tkwin,
XEvent *eventPtr);The tkwin parameter to modalProc will be identical to the tkwin parameter passed to Tk_SetClassProcs. The eventPtr parameter will be a pointer to an XEvent structure
describing the event being processed.
KEYWORDS
- callback, class