Attribute lists – HP SunSoft Pascal 4.0 User Manual

Page 249

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The XView Toolkit

225

10

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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