Objective-C Mapping for Built-In Types

The Slice built-in types are mapped to Objective-C types as shown below.

Slice	Objective-C
`bool`	`BOOL`
`byte`	`ICEByte`
`short`	`ICEShort`
`int`	`ICEInt`
`long`	`ICELong`
`float`	`ICEFloat`
`double`	`ICEDouble`
`string`	`NSString` or `NSMutableString`

Slice bool maps to Objective-C BOOL. The remaining integral and floating-point types map to Objective-C type definitions instead of native types. This allows the Ice run time to provide a definition as appropriate for each target architecture. (For example, ICELong might be defined as long on one architecture and as long long on another.)

Note that ICEByte is a typedef for unsigned char. This guarantees that byte values are always in the range 0..255, and it ensures that right-shifting an ICEByte does not cause sign-extension.

Whether a Slice string maps to NSString or NSMutableString depends on the context. NSMutableString is used in some cases for operation parameters; otherwise, if a string is a data member of a Slice structure, class, or exception, it maps to NSString. (We will discuss these differences in more detail as we cover the mapping of the relevant Slice language features.)

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