commaai / c-capnproto

C library/compiler for the Cap'n Proto serialization/RPC protocol

capnpc-c

This is a C plugin for Cap'n Proto, an efficient protocol for sharing data and capabilities.

This is only the plugin, to properly make use of it you need to download, build and install capnpc and then build and install this project and then you can utilize it as:

capnpc compiler/test.capnp -oc

status

This is a merge of 3 forks of James McKaskill's great work, which has been untouched for a while:

• liamstask's fork
• baruch's fork
• kylemanna's fork

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.

building on linux

git clone https://github.com/opensourcerouting/c-capnproto
cd c-capnproto
git submodule update --init --recursive
autoreconf -f -i -s 
./configure
make
make check