XtGetValues man page on HP-UX

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XtGetValues()							 XtGetValues()

Name
  XtGetValues - query widget resource values.

Synopsis
  void XtGetValues(object, args, num_args)
	 Widget object;
	 ArgList args;
	 Cardinal num_args;

Inputs
  object    Specifies	the  object  whose  resource  values  are  to  be
	    returned; may be of class Object or any subclass thereof.

  args	    Specifies the argument list of name/address pairs  that  con‐
	    tain  the  resource	 names	and  the addresses into which the
	    resource values are to be stored.

  num_args  Specifies the number of arguments in the argument list.

Description
  XtGetValues() retrieves the current values of	 one  or  more	resources
  associated  with  a  widget  instance.   Each element in args is an Arg
  structure which contains the resource name in the  name  field,  and	a
  pointer  to  the  location at which the resource is to be stored in the
  value field.	It is the caller's  responsibility  to	ensure	that  the
  value	 field points to a value of the correct type.  If the value field
  points to allocated memory, the caller is also responsible for  freeing
  that memory.

  If  args  contains  a	 resource  name	 that  is not found in any of the
  resource lists searched, the value at the corresponding address is  not
  modified.

  Many	widget	resource  values are simply copied from the widget to the
  specified address.  When the resource is a  pointer  type  (such  as	a
  string  or pointer to a structure) some widgets will make a copy of the
  pointed to value and store the address of this copy  at  the	specified
  address.   If a copy is made, the caller is responsible for freeing the
  value when done with it.  If no copy is made, then the  returned  value
  points to memory owned by the widget, and the caller must not modify or
  free this value in any way.  None of	the  Intrinsics	 defined  classes
  copy	values in this way, nor do widgets in the Athena Widget set.  See
  the documentation for the particular resource of the particular  widget
  you are using to determine if a copy is made.

  If  a	 resource value which is a pointer type is returned without being
  copied, then the returned value may not remain valid indefinitely.  The
  Intrinsics  specify lifetimes for the following resources: The XtNchil‐
  dren resource of Composite widgets and any callback list  resource  are
  only valid until some operation (such as XtCreateWidget() or XtAddCall‐
  back()) modifies the resource.  The XtNtranslations and XtNaccelerators
  Core	resources  remain  valid  at least until the widget is destroyed.
  The XtNscreen Core resource remains valid until the Display is  closed.
  See  the  documentation  for	the particular resource of the particular
  widget you are using to determine its lifetime.

  The "Background" section below explains  in  detail  how  XtGetValues()
  finds the requested resource values.

Usage
  Generally  you  will use the XtSetArg() macro to initialize the ArgList
  passed to this function.  You can also use XtVaGetValues()  pass  it	a
  variable-length  argument list instead of an ArgList array.  The "Exam‐
  ple" section below shows an example use of this function.

  Note that some widgets provide public functions to query the	value  of
  commonly  used resources.  These functions are generally faster, and it
  is usually better specified whether or not the  caller  must	free  the
  returned value.

  You can set a widget's resources with XtSetValues() or XtVaSetValues().

Example
  You can use XtGetValues() as follows to get widget resources:

     Arg args[10];
     int i;
     String label;
     Dimension margin;
     Pixel color;

     /* set up an argument list */
     i = 0;
     XtSetArg(args[i], XtNlabel, &label); i++;
     XtSetArg(args[i], XtNmargin, &margin); i++;
     XtSetArg(args[i], XtNforeground, &color); i++;

     /* query the values */
     XtGetValues(s, args, i);

     /* label, margin, and color now contain the requested values */
     printf("Widget's label is %s; margin is %d.0, label, margin);
     printf("Widget's label is %s; margin is %d.0, label, margin);

     /* In some widget sets we'd have to free label now. */
     /* XtFree(label); */

Background
  XtGetValues()	 looks	for  resources	named in args using the following
  procedure:

  ·  It searches the normal resource lists for the object, starting  with
     the  resources  of the Object class and proceeding down the subclass
     chain to the class of the object.

  ·  If the object's parent is a subclass  of  constraintWidgetClass,  it
     searches  the  constraint	resource lists of the parent, starting at
     constraintWidgetClass and proceeding down the subclass chain to  the
     constraint resources of the parent's class.

  Once	all  the resources have been fetched from the widget's normal and
  constraint resources list, XtGetValues() calls  the  widget's	 get_val‐
  ues_hook() methods.  get_values_hook() procedures can be used to return
  subpart resource values or constraint subpart resource  values  through
  the  XtGetValues()  interface (see XtGetSubvalues()) and may modify the
  data stored at the location addressed by the value field of  the  argu‐
  ment.	  This	means that a get_values_hook() may be used to make copies
  of data (such as strings) whose resource representation is  a	 pointer.
  The get_values_hook() methods are called as follows:

  ·  If any get_values_hook() methods in the object's class or superclass
     records are non-NULL,  they  are  called  in  superclass-to-subclass
     order.

  ·  If	 the  object's parent is a subclass of constraintWidgetClass, and
     if any of the parent's class or  superclass  records  have	 declared
     ConstraintClassExtension records in the Constraint class part exten‐
     sion field with a record type  of	NULLQUARK  and	if  the	 get_val‐
     ues_hook() field in the extension record is non-NULL, then XtGetVal‐
     ues() calls these get_values_hook() procedures in superclass-to-sub‐
     class order.

Structures
  An Arg is defined as follows:

     typedef struct {
	 String name;
	 XtArgVal value;
     } Arg, *ArgList;

See Also
  XtSetArg(1), XtSetValues(1), XtVaGetValues(1), XtVaSetValues(1),
  get_values_hook(4).

Xt - Resource Management					 XtGetValues()
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