caffi

caffi is the Channel Access Foreign Function Interface.
It uses CFFI <https://pypi.python.org/pypi/cffi>_ to call EPICS channel access library.

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

… warning::

On certain platforms, callback <https://cffi.readthedocs.io/en/stable/using.html#callbacks-old-style>_
might not work. On macOS arm64 platform, the module fails in import and is unusable.

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

Package

RPM
^^^
The SPEC file python-caffi.spec is included. Get the source tarball either from PyPI
or create it by python setup.py sdist, and run::

$ rpmbuild -ta caffi-1.0.0.tar.gz

The binary and source RPM will be created. The package name is python-caffi.

Anaconda
^^^^^^^^
The recipe is included.::

$ conda build conda-recipe

Documents

Latest documents are hosted at Read the Dcos <http://caffi.readthedocs.org>_.

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