Module postcard::source ·
Experimental Postcard Features
Items inside this module require various feature flags, and are not subject to SemVer stability. Items may be removed or deprecated at any point.
experimental-derive feature enables two experimental features:
- Max size calculation
- Message schema generation
Max Size Calculation
This features enables calculation of the Max serialized size of a message as
usize constant called
POSTCARD_MAX_SIZE. It also provides a
#[derive(MaxSize)] macro that can be used for calculating user types.
This is useful for determining the maximum buffer size needed when recieving or sending a message that has been serialized.
NOTE: This only covers the size of “plain” flavored messages, e.g. not with COBS or any other Flavors applied. The overhead for these flavors must be calculated separately.
Please report any missing types, or any incorrectly calculated values.
Message Schema Generation
This feature enables the generation of a schema of a given message at compile
time. At the moment, this is only exposed as a
which is a recursive data structure describing the schema. In the future, it is planned
to provide formatting functions that emit this as a human or machine readable schema.
NOTE: This only covers the schema of “plain” flavored messages, e.g. not with COBS or any other Flavors applied. The format of these flavors must be calculated separately.
Please report any missing types, or any incorrectly calculated schemas.