c-capnproto

C support for Cap'n Proto, an efficient protocol for sharing data and capabilities.

status

This is a fork of James McKaskill's great work, which has been untouched for a while, so I've been bringing it up to date with current cap'n proto progress, and doing some doc/testing work. Should the upstream fork become active again, I'd hope to merge any relevant changes back in.

usage

The compiler directory contains the C language plugin (capnpc-c) for use with the capnp tool: https://capnproto.org/capnp-tool.html.

capnp will by default search $PATH for capnpc-c - if it's on your PATH, you can generate code for your schema as follows:

$ capnp compile -o c myschema.capnp

Otherwise, you can specify the path to the c plugin:

$ capnp compile -o ./capnpc-c myschema.capnp

capnp generates a C struct that corresponds to each capn proto struct, along with read/write functions that convert to/from capn proto form.

TBD whether it will make sense in the future to provide accessor functions for struct members, rather than converting entire structs.