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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