Underlying type
An underlying type is the type that determines a named type’s representation, foundational values, or permitted operations.
Modern C, Third Edition
An underlying type is the integer type used to represent the values of a C enumeration.
- How it is used
- Clarifies how C enumerations represent constants and when portability requires an explicit integer type.
- How deep it goes
- Explains automatic adjustment, signedness variation, impossible ranges, and C23 syntax, while deferring deeper typeof treatment.
- Examples
- Uses wide, narrow, ambiguous large, and explicitly typed eInt, eSig, and e32 enumerations.
- What you can do after
- Evaluate enumeration definitions for portability and specify an underlying type when values or signedness could vary.
100 Go Mistakes and How to Avoid Them
An underlying type is the type that determines the representation and core identity shared by a defined Go type and its underlying type.
- How it is used
- Distinguishes exact type constraints from constraints accepting defined types with a shared underlying type.
- How deep it goes
- Explains the difference between int and ~int through a custom type and a compilation failure.
- Examples
- Uses customInt, a String method, and constraints containing ~int or int.
- What you can do after
- Evaluate generic constraints and choose ~T when defined types sharing T's underlying type should be accepted.
Read how 100 Go Mistakes and How to Avoid Them explains underlying type →
Related concepts
- type aliasequivalent to · A type alias is a declaration that gives an existing type an alternative name without creating a distinct type or representation.
- type assertionused by · A type assertion is a language construct that states or checks that a value has a specified type, with runtime behavior depending on the language.
- enumconfigures · An enum is a type or language construct whose values are selected from a finite set of named alternatives, which may carry associated data.
These guides are generated from the text of Manning books by Manning's knowledge graph and link to the sections they draw on. The full books are available on liveBook and at manning.com.