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Installation instructions for PyEpics3 |
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To install the epics module, use |
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pip install pyepics |
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Or download the source kit from PyPI or Github, unpack that, and use |
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pip install . |
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PyEpics requires Python 3.8 or higher. |
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Epics CA Shared Libraries, and using alternate versions of these |
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===================================================================== |
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Pyepics needs to find and load shared object libraries (DLLs) for Epics Channel |
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Access (libca and libCom) at runtime. Recently-compiled versions of these |
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shared object libraries are included with this distribution for Windows64, |
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MacOS (both x86_64 and arm64), Linux64, and LinuxArm and will be installed into |
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the pyepics installation folder and used by default. These are located under |
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the epics/clibs folder of the source folder. Legacy DLLs for 32-bit Windows |
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and Linux are also included, but should be used with caution. |
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By providing and using these shared libraries, pyepics will work "out of the |
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box" on most OSes and systems without any other Epics libraries installed. |
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There may be some OSes used or some situations for which you will want to use |
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different versions of libca and libCom, especially on systems already using |
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Epics for other applications. One notable example is if you are using |
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pyepics within a Python program or application that has already loaded a |
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version of libca, as a single process can load only one version of a shared |
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library. If you are using the `pcaspy` library or running a python script |
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that loads pyepics from within an epics IOC, you will need to ensure that all |
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libraries loading libca load exactly the same version. |
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To accommodate this situation, pyepics loads libca as late as possible and |
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allows you to set the PYEPICS_LIBCA environmental variable, either globally |
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for the shell running the application or within the python program itself |
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before any real Channel Access is done |
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pyepics module. So, for example, you could do |
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>>> import epics |
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>>> import os |
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>>> os.environ['PYEPCICS_LIBCA']='/usr/local/epics/base-7.0.4/lib/linux-x86_64/libca.so' |
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>>> print(epics.caget('XXX:m1')) |
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-0.2500 |
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You can also test which exact 'libca' was used. For the example above |
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>>> print(epics.ca.find_libca()) |
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'/usr/local/epics/base-7.0.4/lib/linux-x86_64/libca.so' |
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whereas by default this will point to something like |
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'../site-packages/pyepics-3.4.3-py3.8.egg/epics/clibs/linux64/libca.so' |
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Matt Newville <[email protected]> |
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Last Update: 2024-June-12 |
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