About the Resource Manager and System 7.0

The Resource Manager describes the resource types that are available for

your application's use (see Application Resource Types), and the new

technique for reading or writing part of a resource instead of an entire

resource (see Using the Resource Manager). The standard resource types

found in the System file in System 7.0 are listed under

The ability to use partial resources is available only in System 7.0 and later.

To check for the existence of the new partial resource routines, use the

Gestalt function.

A resource consists of data or code stored in a resource file. A resource fork is

the part of a file that contains data used by an application, such as menus,

fonts, and icons. An executable file's code is also stored in the resource fork.

The Resource Manager distinguishes resources by their resource types and

resource IDs. The resource type is always a sequence of four alphanumeric

characters ( including the space character). For instance, 'MENU' is the

resource type for a menu. A resource ID is a number that, together with the

resource type, uniquely identifies a particular resource. Resources can be

created from textual descriptions by resource compilers, such as the Rez

compiler in the Macintosh Programmer's Workshop (MPW).

Note: Your application should not depend on any specific resource being in

ROM or in the System file. The resource types available in ROM vary. A

resource that is in ROM may not be available because the System file may

override any resource in ROM, making it unavailable or replacing it with a

resource from the System file.

Resource Types

A resource type can be any sequence of four alphanumeric characters,

including the space character. You can create resource types for your

applications, provided the type names you choose consist of all uppercase

letters and do not conflict with the resource types already created. Apple

reserves any other combination. (The standard Roman character set can be

found in the Font Manager description.)

The System file contains system resources, the standard resources for the

Macintosh computer that are shared by all applications. The Table in

Application Resource Types lists all the resource types in the System

file that your application can use. Uppercase resource types are listed first.