VistaIOSetAttr(3) set an attribute's value


void VistaIOSetAttr (list, name, dict, repn, value)

VistaIOAttrList list; VistaIOStringConst type; VistaIODictEntry *dict; VistaIORepnKind repn; type value;
void VistaIOSetAttrValue (posn, dict, repn, value)
VistaIOAttrListPosn posn; VistaIODictEntry *dict; VistaIORepnKind repn; type value;
where type, according to repn, is VistaIOBit, VistaIOUByte, VistaIOSByte, VistaIOShort, VistaIOLong, VistaIOFloat, VistaIODouble, VistaIOAttrList, VistaIOBoolean, VistaIOBundle, VistaIOList, VistaIOPointer, VistaIOString, VistaIOEdges, VistaIOImage, etc.


Specifies and returns the attribute list in which an attribute is to be set.
Specifies by name of the attribute to be set.
Specifies by position the attribute to be set.
May specify a dictionary to be used in translating the value supplied to a keyword that should be stored as the attribute's value, or it may be NULL
Specifies the representation of the new attribute value.
Specifies the new attribute value.


These routines both set an attribute's value, but they differ in how the attribute is identified:
  • VistaIOSetAttr sets the value of an attribute named name in the attribute list list. If list does not already contain an attribute named name then a new attribute with that name is appended to it. Otherwise, only the first attribute named name is located and changed.
  • VistaIOSetAttrValue sets the value of the attribute whose position within an attribute list is posn.

With the dict argument you can provide a dictionary for mapping value to a keyword that will be stored as the attribute's value (see VistaIOdictionary(3)). For example, if you pass an attribute value of 1 and a dictionary that associates the value 1 with the keyword ubyte (as the dictionaryVistaIORepnDict does), then the string ubyte will be stored as the attribute's value. Dictionaries may be used to map both numeric values and strings to keywords. If you supply a dictionary but value is not mentioned in that dictionary, then value itself will be stored with the attribute.

If value is a number or character string, the routine makes its own copy of the value as a character string for storing in the attribute. If, on the other hand, value is an attribute list, pointer, image, edge set, etc., then the routine stores a pointer in the attribute but it does not make a copy of the object pointed to.


As a side effect, these routines modify the attribute list referred to by list or posn.


The following code fragment sets an image's name:

VistaIOImage image; VistaIOSetAttr (VistaIOImageAttrList (image), VistaIONameAttr, NULL,
VistaIOStringRepn, "Mona Lisa");


Art Pope <[email protected]>

Adaption to vistaio: Gert Wollny <[email protected]>