Inside Macintosh: Files /

Chapter 1 - Introduction to File Management

This chapter is a general introduction to file management on Macintosh computers. It explains the basic structure of Macintosh files and the hierarchical file system (HFS) used with Macintosh computers, and it shows how you can use the services provided by the Standard File Package, the File Manager, the Finder, and other system software components to create, open, update, and close files.

You should read this chapter if your application implements the commands typically found in an application's File menu--except for printing commands and the Quit command, which are described elsewhere. This chapter describes how to

• create a new file
• open an existing file
• close a file
• save a document's data in a file
• save a document's data in a file under a new name
• revert to the last saved version of a file
• create and read a preferences file

Depending on the requirements of your application, you may be able to accomplish all your file-related operations by following the instructions given in this chapter. If your application has more specialized file management needs, you'll need to read some or all of the remaining chapters in this book.

This chapter assumes that your application is running in an environment in which the routines that accept file system specification records (defined by the FSSpec data type) are available. File system specification records, introduced in system software version 7.0, simplify the identification of objects in the file system. Your development environment may provide "glue" that allows you to call those routines in earlier system software versions. If such glue is not available and you want your application to run in system software versions earlier than version 7.0, you need to read the discussion of HFS file-manipulation routines in the chapter "File Manager" in this book.

This chapter begins with a description of files and their organization into directories and volumes. Then it describes how to test for the presence of the routines that accept FSSpec records and how to use those routines to perform the file management tasks listed above. The chapter ends with descriptions of the data structures and routines used to perform these tasks. The "File Management Reference" and "Summary of File Management" sections in this chapter are subsets of the corresponding sections of the remaining chapters in this book.

---

Chapter Contents

About Files

File Forks

File Size

File Access Characteristics

The Hierarchical File System

Identifying Files and Directories

Using Files

Testing for File Management Routines

Defining a Document Record

Creating a New File

Opening a File

Reading File Data

Writing File Data

Saving a File

Reverting to a Saved File

Closing a File

Opening Files at Application Startup Time

Using a Preferences File

Adjusting the File Menu

File Management Reference

Data Structures

File System Specification Record

Standard File Reply Records

Application Files Records

File Specification Routines

File Access Routines

Reading, Writing, and Closing Files

Manipulating the File Mark

Manipulating the End-of-File

File and Directory Manipulation Routines

Opening, Creating, and Deleting Files

Exchanging the Data in Two Files

Creating File System Specifications

Volume Access Routines

Updating Volumes

Obtaining Volume Information

Application Launch File Routines

Summary of File Management

Pascal Summary

Constants

Data Types

File System Specification Record

Standard File Reply Record

Application Files Record

File Specification Routines

Opening Files

Saving Files

File Access Routines

Reading, Writing, and Closing Files

Manipulating the File Mark

Manipulating the End-of-File

File and Directory Manipulation Routines

Opening, Creating, and Deleting Files

Exchanging the Data in Two Files

Creating File System Specifications

Volume Access Routines

Updating Volumes

Obtaining Volume Information

Application Launch File Routines

C Summary

Constants

Data Types

File System Specification Record

Standard File Reply Record

Application Files Record

Standard File Type List

Callback Routine Pointer Types

File Specification Routines

Opening Files

Saving Files

File Access Routines

Reading, Writing, and Closing Files

Manipulating the File Mark

Manipulating the End-of-File

File and Directory Manipulation Routines

Opening, Creating, and Deleting Files

Exchanging the Data in Two Files

Creating File System Specifications

Volume Access Routines

Updating Volumes

Obtaining Volume Information

Application Launch File Routines

Assembly-Language Summary

Global Variables

Result Codes