Inside Macintosh: Processes

Chapter 7 - Segment Manager

This chapter describes the Segment Manager, the part of the Macintosh Operating System that loads and unloads your application's code segments into and out of memory. By dividing your application's executable code into segments, you allow it to run in a memory partition that is smaller than the total size of the application itself and the data it is using.

To use this chapter, you should already be familiar with the basic concepts of the Resource Manager and the Memory Manager. You need to know about the basic operation of the Resource Manager because segments are stored as resources. You need to know about the basic operation of the Memory Manager to understand when and why segments might be purged from memory. See the chapter "Introduction to Memory Management" in Inside Macintosh: Memory.

You should read this chapter if your application contains multiple code segments that do not all need to be in memory at one time.

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Chapter Contents

About the Segment Manager

Code Segmentation

The Jump Table

Using the Segment Manager

Unloading Code Segments

Loading Code Segments

Segment Manager Reference

Routine

Summary of the Segment Manager

Pascal Summary

Routine

C Summary

Routine

Assembly-Language Summary

Global Variables

Advanced Routine