CEnum.jl

CEnum.jl provides @cenum, an enum type for Julia that behaves like an enum in C. It is meant for wrapping C libraries, and is what Clang.jl emits for the enums it finds in C headers.

Base.@enum is stricter than C: every name needs its own value, and a variable of the enum type can only hold one of the named values. C code relies on neither being true, so translated headers often cannot use it:

julia> @enum Foo a = 1 b = 2 c = 1
ERROR: LoadError: ArgumentError: values for Enum Foo are not unique

With @cenum the same definition works:

julia> using CEnum

julia> @cenum Bar d = 1 e = 2 f = 1

julia> d == f
true

Installation

julia> import Pkg; Pkg.add("CEnum")

CEnum.jl has no dependencies and supports Julia 1.6 and later.

Differences from Base.@enum

A type defined with @cenum

• allows several names for the same value;
• can hold any value of its base type, not only the named ones, so results of bitwise operations and values returned by C code are always representable;
• compares equal to integers and to members of other @cenum types that have the same value, and hashes like the integer;
• supports integer arithmetic and bitwise operators, which return plain integers.

See the Guide for each of these in turn.