caffi 1.0.0b3

Channel Access Foreign Function Interface

caffi is the Channel Access Foreign Function Interface. It uses CFFI to call EPICS channel access library.

This package provides direct low level interface to channel access, alike the C API.

Note

cffi commit 9fe2a9e contains an important fix to the frequent hangup on Windows 64bit Python 3. That means until cffi 1.11 is released, one should patch manually.

Install

EPICS dynamic libraries have been shipped with the package for Windows, Linux and macOS. But if the environment variables EPICS_BASE and EPICS_HOST_ARCH are set on macOS and Linux, those libraries under path ${EPICS_BASE}/lib/${EPICS_HOST_ARCH} will be used.

Either use pip,

$ pip install caffi

or checkout source code from the git repository,

$ git clone https://github.com/CaChannel/caffi.git
$ cd caffi
$ python setup.py install

Documents

Latest documents are hosted at Read the Dcos.

Example

import caffi.ca as ca

status = ca.create_context()
assert status == ca.ECA.NORMAL

status, chid = ca.create_channel('catest')
assert status == ca.ECA.NORMAL

status = ca.pend_io(3)
assert status == ca.ECA.NORMAL

status = ca.put(chid, 123)
status = ca.flush_io()

status, value = ca.get(chid)
assert status == ca.ECA.NORMAL

status = ca.pend_io(3)
assert status == ca.ECA.NORMAL

assert value.get() == 123