Length
base: intFIX 4.4FIX 4.2FIX 5.0 SP2
Length is a FIX datatype defined in FIX 4.4, FIX 4.2 and FIX 5.0 SP2, carried on the wire as int. 18 fields use it.
Wire format
- Base type
- int
- Fields
- 18
A byte count for the length-prefixed field that follows it. Count bytes, not characters — a multi-byte UTF-8 value makes the two differ.
What the specification says
FIX 4.4
int field representing the length in bytes. Value must be positive.
FIX 5.0 SP2
Sequence of digits without commas or decimals. Value must be positive.
Descriptions are quoted from the FIX Orchestra sources under the Apache 2.0 licence.
How @boarteam/fix handles it
@boarteam/fix parses the value as a number and reports parse/invalid-int when it does not lex as one; the raw string is kept either way.
Fields with this datatype
Decode this in your own code
The same engine that produced the decoded example above is an Apache-2.0 npm package with zero runtime dependencies. It runs in Node and in the browser, and parse() returns problems as data instead of throwing.
npm i @boarteam/fix @boarteam/fix-dict-fix44