xmresolvepartoffsets(3x) [osf1 man page]

XmResolvePartOffsets(3X)												  XmResolvePartOffsets(3X)

NAME

       XmResolvePartOffsets - A function that allows writing of upward-compatible applications and widgets

SYNOPSIS

       #include <Xm/XmP.h>

       void XmResolvePartOffsets (widget_class, offset)
	       WidgetClass widget_class;
	       XmOffsetPtr * offset;

DESCRIPTION

       The  use  of  offset records requires one extra global variable per widget class. The variable consists of a pointer to an array of offsets
       into the widget record for each part of the widget structure. The XmResolvePartOffsets function allocates the offset records needed  by	an
       application to guarantee upward-compatible access to widget instance records by applications and widgets.  These offset records are used by
       the widget to access all of the widget's variables. A widget needs to take the following steps: Instead of creating a  resource	list,  the
       widget  creates	an  offset  resource  list.  To help you accomplish this, use the XmPartResource structure and the XmPartOffset macro. The
       XmPartResource data structure looks just like a resource list, but instead of having one integer for its offset, it has two shorts. This is
       put into the class record as if it were a normal resource list.	Instead of using XtOffset for the offset, the widget uses XmPartOffset.

	      XmPartResource resources[] = {
		{ BarNxyz, BarCXyz, XmRBoolean,
		  sizeof(Boolean), XmPartOffset(Bar,xyz),
		  XmRImmediate, (XtPointer)False } }; Instead of putting the widget size in the class record, the widget puts the widget part size
	      in the same field.  Instead of putting XtVersion in the class record, the widget puts XtVersionDontCheck in the class  record.   The
	      widget  defines  a  variable, of type XmOffsetPtr, to point to the offset record. This can be part of the widget's class record or a
	      separate global variable.  In class initialization, the widget calls XmResolvePartOffsets, passing  it  a  pointer  to  contain  the
	      address  of the offset record and the class record. This does several things: Adds the superclass (which, by definition, has already
	      been initialized) size field to the part size field.  Allocates an array based upon the number of superclasses.  Fills in  the  off-
	      sets  of	all the widget parts with the appropriate values, determined by examining the size fields of all superclass records.  Uses
	      the part offset array to modify the offset entries in the resource list to be real offsets.  The widget  defines	a  constant  which
	      will  be	the  index to its part structure in the offsets array. The value should be 1 greater than the index of the widget's super-
	      class. Constants defined for all Xm widgets can be found in <XmP.h>.

	      #define BarIndex (XmBulletinBIndex + 1) Instead of accessing fields directly, the widget must always go through  the  offset  table.
	      The  XmField  macro helps you access these fields. Because the XmPartOffset and XmField macros concatenate things together, you must
	      ensure that there is no space after the part argument. For example, the following macros do not work because of the space after  the
	      part (Label) argument:

	      XmField(w, offset, Label , text, char *) XmPartOffset(Label , text)

	      Therefore, you must not have any spaces after the part (Label) argument, as illustrated here:

	      XmField(w, offset, Label, text, char *)

	      You can define macros for each field to make this easier. Assume an integer field xyz:

	      #define BarXyz(w) (*(int *)(((char *) w) + 
		offset[BarIndex] + XtOffset(BarPart,xyz)))

       The  parameters	for XmResolvePartOffsets are defined below: Specifies the widget class pointer for the created widget.	Returns the offset
       record.

SEE ALSO

       XmResolveAllPartOffsets(3X)

															  XmResolvePartOffsets(3X)

XmResolveAllPartOffsets(library call)									     XmResolveAllPartOffsets(library call)

NAME

       XmResolveAllPartOffsets -- A function that allows writing of upward-compatible applications and widgets

SYNOPSIS

       #include <Xm/Xm.h>
       void XmResolveAllPartOffsets(
       WidgetClass widget_class,
       XmOffsetPtr * offset,
       XmOffsetPtr * constraint_offset);

DESCRIPTION

	      Note:

	      This routine is obsolete and exists for compatibility with previous releases. You should call XmeResolvePartOffsets instead.

       The  use  of  offset  records requires two extra global variables per widget class.  The variables consist of pointers to arrays of offsets
       into the widget record and constraint record for each part of the widget structure.  The  XmResolveAllPartOffsets  function  allocates  the
       offset records needed by an application to guarantee upward-compatible access to widget instance and constraint records by applications and
       widgets.  These offset records are used by the widget to access all of the widget's variables.  A widget needs to take the steps  described
       in the following paragraphs.

       Instead	of creating a resource list, the widget creates an offset resource list.  To accomplish this, use the XmPartResource structure and
       the XmPartOffset macro.	The XmPartResource data structure looks just like a resource list, but instead of having one integer for its  off-
       set,  it  has  two shorts.  This structure is put into the class record as if it were a normal resource list. Instead of using XtOffset for
       the offset, the widget uses XmPartOffset.

       If the widget is a subclass of the Constraint class and it defines additional constraint resources, create an offset resource list for  the
       constraint part as well.  Instead of using XtOffset for the offset, the widget uses XmConstraintPartOffset in the constraint resource list.

       XmPartResource resources[] = {
	       {       BarNxyz, BarCXyz, XmRBoolean, sizeof(Boolean),
		       XmPartOffset(Bar,xyz), XmRImmediate, (XtPointer)False } };
       XmPartResource constraints[] = {
	       {       BarNmaxWidth, BarNMaxWidth,
		 XmRDimension, sizeof(Dimension),
		 XmConstraintPartOffset(Bar,max_width),
		 XmRImmediate, (XtPointer)100 } };

       Instead	of  putting  the widget size in the class record, the widget puts the widget part size in the same field.  If the widget is a sub-
       class of the Constraint class, instead of putting the widget constraint record size in the class record, the widget puts  the  widget  con-
       straint part size in the same field.

       Instead of putting XtVersion in the class record, the widget puts XtVersionDontCheck in the class record.

       Define a variable, of type XmOffsetPtr, to point to the offset record.  If the widget is a subclass of the Constraint class, define a vari-
       able of type XmOffsetPtr to point to the constraint offset record.  These can be part of the widget's class record or separate global vari-
       ables.

       In  class  initialization,  the	widget	calls  XmResolveAllPartOffsets, passing it pointers to the class record, the address of the offset
       record, and the address of the constraint offset record.  If the widget not is a subclass of the Constraint class, it should pass  NULL	as
       the address of the constraint offset record.  This does several things:

	  o  Adds the superclass (which, by definition, has already been initialized) size field to the part size field

	  o  If the widget is a subclass of the Constraint class, adds the superclass constraint size field to the constraint size field

	  o  Allocates an array based upon the number of superclasses

	  o  If the widget is a subclass of the constraint class, allocates an array for the constraint offset record

	  o  Fills  in	the  offsets  of  all  the widget parts and constraint parts with the appropriate values, determined by examining the size
	     fields of all superclass records

	  o  Uses the part offset array to modify the offset entries in the resource list to be real offsets, in place

       The widget defines a constant that will be the index to its part structure in the offsets array.  The value should be 1	greater  than  the
       index of the widget's superclass.  Constants defined for all Xm widgets can be found in XmP.h.

       #define BarIndex (XmBulletinBIndex + 1)

       Instead	of  accessing  fields directly, the widget must always go through the offset table.  The XmField and XmConstraintField macros help
       you access these fields.  Because the XmPartOffset, XmConstraintPartOffset, XmField, and XmConstraintField macros concatenate  things,  you
       must  ensure  that there is no space after the part argument.  For example, the following macros do not work because of the space after the
       part (Label) argument:

       XmField(w, offset, Label, text, char *)
       XmPartOffset(Label, text).

       Therefore, you must not have any spaces after the part (Label) argument, as illustrated here:

       XmField(w, offset, Label, text, char *)

       You can define macros for each field to make this easier.  Assume an integer field xyz:

       #define BarXyz(w) (*(int *)(((char *) w) + 
	       offset[BarIndex] + XtOffset(BarPart,xyz)))

       For constraint field max_width:

       #define BarMaxWidth(w) 
	       XmConstraintField(w,constraint_offsets,Bar,max_width,Dimension)

       The parameters for XmResolveAllPartOffsets are

       widget_class
		 Specifies the widget class pointer for the created widget

       offset	 Returns the offset record

       constraint_offset
		 Returns the constraint offset record

RELATED INFORMATION

       XmResolvePartOffsets(3).

													     XmResolveAllPartOffsets(library call)