
The XView Toolkit 225
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Instead of these routines, the Pascal interface to XView defines a separate
routine to get and set each attribute.
• set—The routine to set an attribute is called set_attrname. Each set
routine is a procedure, and takes as its first argument the object for which
the attribute is being set. The second argument is the value of the attribute.
• get—The routine to get the value of an attribute is called get_attrname.
Each get routine is a function, and takes an XView object as the first
argument. It returns the value of the attribute requested.
For example:
These routines are defined in the header file, attrgetset_p.h.
Attribute Lists
Some of the XView C routines can optionally take extra arguments that are lists
of attributes and values. The extra arguments vary in number and type. You
must pass a 0 to the last argument of these routines.
Since Pascal does not support variable length argument lists, the Pascal
definition has a single argument.
Instead, special versions of these routines are provided which take as a last
argument an argument of type Attr_avlist. This type is a pointer to an
array of attributes and values. The special routines are:
xv_init_l(),
xv_create_l(),
xv_find_l(),
selection_ask_l(),
selection_init_request_l().
set_WIN_SHOW ( frame, true );
width := get_CANVAS_WIDTH ( canvas );
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