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.
- const Tk_ClassProcs *procs (in)
- Pointer to data structure containing widget specific 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 parameter 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_ClassCreateProc:
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_SetClassProcs. 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