Tk_SetClassProcs(3) Tk Library Procedures Tk_SetClassProcs(3)______________________________________________________________________________NAMETk_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 con‐
taining widget specific proce‐
dures. 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.
_________________________________________________________________DESCRIPTIONTk_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. world‐
ChangedProc 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 iden‐
tical 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_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 cre‐
ateProc 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 parame‐
ter passed to Tk_SetClassProcs. The eventPtr parameter will be a
pointer to an XEvent structure describing the event being processed.
KEYWORDS
callback, class
Tk 8.4 Tk_SetClassProcs(3)
