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paperh18648 margl-907 margr0 margt0 margb0 fi0 ri0 ql sb0 f1 fs24 Copyright f3 'e3f1 1994 by NeXT Computer, Inc. All Rights Reserved.
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fs36 NSValue
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fs28 f0 b fs24 Inherits From:tab b0 fs28 f1 NSObject
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fs28 s11 f0 b fs24 Conforms To:tab b0 fs28 f1 NSCoding, NSCopying
fi0 NSObject (NSObject)
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fs28 s12 fi-2771 f0 b fs24 Declared In:tab b0 fs28 f1 Foundation/NSValue.h
fi0 Foundation/NSGeometry.h
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fs28 Class Description
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fs28 NSValue objects provide an object-oriented wrapper for the data types defined in standard C and Objective C. The NSValue class is often used to put Objective C and standard C data types into collections that require objects, such as NSArray objects. When a value object is instantiated, it is encoded with the specified data type.
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fs28 The NSValue class declares the programmatic interface to an object that contains a C data type. It provides methods for creating value objects that contain values of a specified data type, pointers, and other objects.
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fs28 Use NSValue objects to put C types into collections. Use NSNumber objects to put numbers into collections.
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fs28 The following code puts an NSRange into an NSArray, using the Objective C b @encodeb0 directive to get a character string that encodes the type structure of NSRange:
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fs28 pard s9 li1231 fi0 ri1007 ql f2 fs20 [myArray insertObject:[NSValue value:&range withObjCType:@encode(NSRange)] atIndex:n]
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fs28 To get the value back, you would do this:
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fs28 pard s9 li1231 fi0 ri1007 ql f2 fs20 [[myArray objectAtIndex:n] getValue:&range]
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fs28 NSValue objects are provided with generic coding and copying behavior. To subclass NSValue and preserve class when encoding or copying, override b classForCoderb0 , b initWithCoder:,b0 b encodeWithCoder:b0 (for encoding), and b copyWithZone:b0 (for copying).
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fs28 General Exception Conditions
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fs28 NSValue can raise NSInternalInconsistencyException in a variety of cases where an unkown Objective C type is found. In addition, NSValue'27s implementation of b encodeWithCoder:b0 can raise NSInvalidArgumentException if an attempt is made to encode b voidb0 .
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fs28 Allocating and Initializing Value Objects
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fs28 fi-6552 + (NSValue *)b value:b0 (const void *)i valuei0 tab Creates and returns a value object containing the value
s14 li7030 fi-6553 fi-5796 b withObjCType:b0 (const char *)i typei0 tab i tab valuei0 of the Objective C type i typei0 .
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fs28 fi-6552 + (NSValue *)b valueWithNonretainedObject:b0 (id)i anObject
s14 li7030 fi-6553 fi-5796 i0 tab Creates and returns a value object containing the object i anObject,i0 without retaining i anObjecti0 . fs28 This is provided as a convenience method: the statement fs28 [NSValue valueWithNonretainedOject:i anObjecti0 ] is equivalent to the statement [NSValue value:&i anObjecti0 withObjCType:@encode(void *)].
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fs28 fi-6552 + (NSValue *)b valueWithPointer:b0 (const void *)i pointer
s14 li7030 fi-6553 fi-5796 i0 tab Creates and returns a value object that contains the specified pointer.fs28 This is provided as a convenience method: the statement fs28 [NSValue valueWithPointer:i pointeri0 ] is equivalent to the statement [NSValue value:&i pointeri0 withObjCType:@encode(void *)].
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fs28 Allocating and Initializing Geometry Value Objects
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fs28 fi-6552 + (NSValue *)b valueWithPoint:b0 (NSPoint)i pointtab i0 Creates and returns a value object that contains the specifiedi i0 NSPoint structure (which represents a geometrical point in two dimensions).
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fs28 fi-6552 + (NSValue *)b valueWithRect:b0 (NSRect)i recttab i0 Creates and returns a value object that contains the specifiedi i0 NSRect structure, representing a rectangle.
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fs28 fi-6552 + (NSValue *)b valueWithSize:b0 (NSSize)i sizei0 tab Creates and returns a value object that contains the specifiedi i0 NSSize structure (which stores a width and a height).
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fs28 Accessing Data in Value Objects
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fs28 fi-6552 {f3 -} (void)b getValue:b0 (void *)i valuei0 tab Copies the receiver'27s data into i valuei0 .
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fs28 fi-6552 {f3 -} (id)b nonretainedObjectValueb0 tab Returns the non-retained object that'27s contained in the receiver. It'27s an error to send this message to an NSValue object that doesn'27t store a nonretained object.
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fs28 fi-6552 {f3 -} (const char *)b objCTypeb0 tab Returns the Objective C type of the data contained in the receiver.
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fs28 fi-6552 {f3 -} (void *)b pointerValueb0 tab Returns the value pointed to by a pointer contained in an value object. It'27s an error to send this message to an NSValue that doesn'27t store a pointer.
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fs28 Accessing Data in Value Geometry Objects
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fs28 fi-6552 {f3 -} (NSPoint)b pointValueb0 tab Returns the point structure that'27s contained in the receiver.
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fs28 fi-6552 {f3 -} (NSRect)b rectValueb0 tab Returns the rectangle structure that'27s contained in the receiver.
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fs28 fi-6552 {f3 -} (NSSize)b sizeValuetab b0 Returns the size structure that'27s contained in the receiverb .
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}These are the contents of the former NiCE NeXT User Group NeXTSTEP/OpenStep software archive, currently hosted by Netfuture.ch.