Inside Macintosh: Processes

Chapter 2 - Process Manager

About the Process Manager

The Process Manager schedules the processing of all applications and desk accessories. It allows multiple applications to share CPU time and other resources. Applications share the available memory and access to the CPU. Several applications can be open (loaded into memory) at once, but only one uses the CPU at any one time.

Note

For a complete description of how the Process Manager schedules applications and desk accessories for execution, see the chapter "Introduction to Processes and Tasks" in this book. ·

The Process Manager also provides a number of routines that allow you to control the execution of processes and to get information about processes, including your own. You can use the Process Manager routines to

• control the execution of your application
• get information about processes
• launch other applications
• launch desk accessories

The Process Manager assigns a process serial number to each open application (or desk accessory, if it is not opened in the context of an application). The process serial number is unique to each process on the local computer and is valid for a single boot of the computer. You can use the process serial number to specify a particular process for most Process Manager routines.

When a user opens or prints a file from the Finder, it uses the Process Manager to launch the application that created the file. The Finder sets up the information from which your application can determine which files to open or print. The Finder information includes a list of files to open or print.

In system software version 7.0 and later, applications that support high-level events (that is, that have the isHighLevelEventAware flag set in the 'SIZE' resource) receive the Finder information through Apple events. The chapter "Apple Event Manager" in Inside Macintosh: Interapplication Communication describes how your application processes Apple events to open or print files.

Applications that do not support high-level events can call the CountAppFiles, GetAppFiles, and ClrAppFiles routines or the GetAppParms routine to get the Finder information. See the chapter "Introduction to File Management" in Inside Macintosh: Files for information on these routines.