Initial byte and arguments
01The first byte carries a three-bit major type and five-bit additional information.
Related RFCs and changes
“Updates” changes part of an earlier RFC. “Obsoletes” replaces it. This list shows selected related documents.
DIAGRAM§ 3.1 ↗
RFC 8949 · § 3.1EXAMPLE
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03
Interpret the type
Type 1 with argument 499 represents −500.
Protocol participantThreat or exceptionProtocol controlSimplified drawings · precise section references
RFC 7049RFC 8949 Appendix G
The new specification keeps full format compatibility, corrects errata, and clarifies deterministic encoding. It explicitly does not create a new CBOR format version.
Read the updated RFC section ↗Small arguments 0–23 are inline; larger values use following bytes.
- Small arguments 0–23 are inline; larger values use following bytes.
- Major types distinguish integers, strings, containers, tags, and simple/float values.
- Negative integers use value −1 minus the unsigned argument.
Examples are illustrative. Consult the linked RFC and its errata for implementation details.
Read the RFC section ↗Diagrams simplify the RFC. Read the linked sections for complete requirements.
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