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3

Common Classes and Functions

	Library:	libsys_s.a
	Header File Directories:	/NextDeveloper/Headers/objc /NextDeveloper/Headers/streams /NextDeveloper/Headers/defaults /NextDeveloper/Headers/appkit
	Import:	appkit/appkit.h or individual header files

Introduction

The classes and functions described in this chapter can serve a wide variety of different kinds of applications.  They get the name "common" from the fact that they're generally useful and commonly used.  Most provide ways of managing data and resources within a program.  They can be used in conjunction with any of the NEXTSTEP software kits.

Figure 3-1.  Common Classes Inheritance Hierarchy The table below is a guide to the facilities documented here.  The first column states, in a few words, a kind of data-management or resource-management service.  The second column says where to look in the chapter; it names the class or principal function that provides the service.  Consult the documentation for the functions and classes mentioned to learn whether they're right for your application.

	Facility	Class or Function
	Storage allocation	NXZoneMalloc() NXCreateZone() NXMallocCheck() Storage class
	Unordered collections	HashTable class NXCreateHashTable() NXHashInsert() NXStringTable class
	Ordered collections	List class Storage class
	Recording user preferences	NXRegisterDefaults()
	Localizing resources	NXBundle class NXLocalizedString()
	Exception handling	NX_RAISE() NXDefaultExceptionRaiser() NXSetUncaughtExceptionHandler() NXAllocErrorData()
	Dynamic loading of code	NXBundle class
	Input-output streams	NXOpenFile() NXOpenMemory() NXRead() NXPutc()
	Archiving	NXOpenTypedStream()
	and typed streams	NXReadObject() NXReadType()
	Classifying and	NXIsAlpha()
	converting characters	NXToAscii()

Because the Application Kit makes use of all the common classes and almost all of the common functions, importing the appkit.h header file automatically imports all but one of the header files that declare common classes and functions.  Since appkit.h corresponds to a precompiled version of the header files, importing it rather than individual files dramatically reduces the time required for compilation.  The only common header file that's omitted, and that you might need to import individually, is streams/streamsimpl.h.  It declares rarely used functions that implement new versions of a stream.