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Tk_CreateBindingTable(3)     Tk Library Procedures    Tk_CreateBindingTable(3)




NAME

       Tk_CreateBindingTable,     Tk_DeleteBindingTable,     Tk_CreateBinding,
       Tk_DeleteBinding, Tk_GetBinding,  Tk_GetAllBindings,  Tk_DeleteAllBind-
       ings, Tk_BindEvent - invoke scripts in response to X events


SYNOPSIS

       #include <tk.h>

       Tk_BindingTable
       Tk_CreateBindingTable(interp)

       Tk_DeleteBindingTable(bindingTable)

       unsigned long
       Tk_CreateBinding(interp, bindingTable, object, eventString, script, append)

       int
       Tk_DeleteBinding(interp, bindingTable, object, eventString)

       const char *
       Tk_GetBinding(interp, bindingTable, object, eventString)

       Tk_GetAllBindings(interp, bindingTable, object)

       Tk_DeleteAllBindings(bindingTable, object)

       Tk_BindEvent(bindingTable, eventPtr, tkwin, numObjects, objectPtr)


ARGUMENTS

       Interpreter  to use when invoking bindings in binding table.  Also used
       for returning results and errors from binding  procedures.   Token  for
       binding  table;   must  have  been  returned  by  some previous call to
       Tk_CreateBindingTable.  Identifies object with which binding is associ-
       ated.   String  describing  event  sequence.  Tcl script to invoke when
       binding triggers.  Non-zero means append script to existing script  for
       binding,  if  any;  zero means replace existing script with new one.  X
       event to match against bindings in bindingTable.   Identifier  for  any
       window  on the display where the event occurred.  Used to find display-
       related information such as key maps.   Number  of  object  identifiers
       pointed  to  by  objectPtr.   Points to an array of object identifiers:
       bindings will be considered for each of these  objects  in  order  from
       first to last.



DESCRIPTION

       These  procedures  provide a general-purpose mechanism for creating and
       invoking bindings.  Bindings are organized in terms of binding  tables.
       A  binding table consists of a collection of bindings plus a history of
       recent events.  Within a binding table, bindings  are  associated  with
       objects.  The meaning of an object is defined by clients of the binding
       package.  For example, Tk keeps uses one binding table to hold  all  of
       the  bindings created by the bind command.  For this table, objects are
       pointers to strings such as window names, class names, or other binding
       tags such as all.  Tk also keeps a separate binding table for each can-
       vas widget, which manages bindings created by the canvas's bind  widget
       command;   within  this  table,  an  object  is either a pointer to the
       internal structure for a canvas item or a Tk_Uid identifying a tag.

       The procedure Tk_CreateBindingTable creates a new binding table and as-
       sociates  interp  with  it (when bindings in the table are invoked, the
       scripts will be evaluated in interp).  Tk_CreateBindingTable returns  a
       token  for  the  table, which must be used in calls to other procedures
       such as Tk_CreateBinding or Tk_BindEvent.

       Tk_DeleteBindingTable frees all of the state associated with a  binding
       table.   Once  it  returns  the  caller should not use the bindingTable
       token again.

       Tk_CreateBinding adds a new binding to an existing table.   The  object
       argument  identifies the object with which the binding is to be associ-
       ated, and it may be any one-word value.  Typically it is a pointer to a
       string  or  data  structure.   The  eventString argument identifies the
       event or sequence of events for the binding;  see the documentation for
       the  bind  command  for a description of its format.  script is the Tcl
       script to be evaluated when the  binding  triggers.   append  indicates
       what   to  do  if  there  already  exists  a  binding  for  object  and
       eventString:  if append is zero then script replaces  the  old  script;
       if  append  is non-zero then the new script is appended to the old one.
       Tk_CreateBinding returns an X event mask for all the events  associated
       with the bindings.  This information may be useful to invoke XSelectIn-
       put to select relevant events, or to disallow the use of certain events
       in  bindings.   If  an error occurred while creating the binding (e.g.,
       eventString refers to a non-existent event), then 0 is returned and  an
       error message is left in interp->result.

       Tk_DeleteBinding  removes from bindingTable the binding given by object
       and eventString, if such a  binding  exists.   Tk_DeleteBinding  always
       returns  TCL_OK.   In  some  cases  it  may reset interp->result to the
       default empty value.

       Tk_GetBinding  returns  a  pointer  to  the  script   associated   with
       eventString and object in bindingTable.  If no such binding exists then
       NULL is returned and an error message is left in interp->result.

       Tk_GetAllBindings returns in interp->result a list  of  all  the  event
       strings  for  which  there are bindings in bindingTable associated with
       object.  If there are no bindings for object then an  empty  string  is
       returned in interp->result.

       Tk_DeleteAllBindings  deletes  all of the bindings in bindingTable that
       are associated with object.

       Tk_BindEvent is called to process an event.  It makes  a  copy  of  the
       event  in  an  internal history list associated with the binding table,
       then it checks for bindings that match the  event.   Tk_BindEvent  pro-
       cesses  each  of the objects pointed to by objectPtr in turn.  For each
       object, it finds all the bindings that match the current event history,
       selects   the  most  specific  binding  using  the  priority  mechanism
       described in the documentation for bind, and  invokes  the  script  for
       that  binding.   If  there  are  no  matching bindings for a particular
       object, then the object is skipped.  Tk_BindEvent continues through all
       of the objects, handling exceptions such as errors, break, and continue
       as described in the documentation for bind.



KEYWORDS

       binding, event, object, script



Tk                                    4.0             Tk_CreateBindingTable(3)

BindTable 8.5.4 - Generated Fri Aug 22 18:08:04 CDT 2008
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