Bit field
A bit field is a designated group of bits within a value or storage unit that represents a data component.
Refactoring to Rust
A bitfield is a structure field occupying a specified number of individual bits rather than a whole storage unit.
- How it is used
- Uses bit fields when configuring NGINX response buffers through Rust foreign-function interfaces.
- How deep it goes
- Defines bit fields and demonstrates generated accessors, stopping short of implementing native Rust bit-field support.
- Examples
- Demonstrates memory, last_buf, and last_in_chain as one-bit fields on ngx_buf_t.
- What you can do after
- Operate NGINX bit-field flags through bindgen-generated setter functions.
Modern C, Third Edition
A bit-field is a C structure or union member declared with a specified number of bits rather than a complete storage-unit width.
- How it is used
- Uses bit fields to reduce structure storage when values need fewer bits than their declared integer types.
- How deep it goes
- Explains declaration syntax, compiler coalescing, member access, storage estimates, and signedness hazards, but not complete layout rules.
- Examples
- Uses calendar-style fields for seconds, minutes, hours, dates, weekdays, year, and daylight-saving status.
- What you can do after
- Build it from scratch by declaring compact C structure fields, accessing them normally, and checking signedness choices.
Related concepts
- memory locationpart of · A memory location is an identifiable address or storage region in computer memory where data or instructions can reside or be accessed.
- unsigned integerconfigured by · An unsigned integer is an integer type or representation whose values are nonnegative, with its representable range determined by its bit width and applicable rules.
- containerpart of · A container is a structure or entity that holds, groups, or packages other data or elements.
- bit paddingaddresses · Bit padding is unused storage at the bit level within a representation, including bits that do not fall on byte boundaries.
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