Runtime Environment¶
The pyDevSup module initializes the interpreter during the registration phase of IOC startup with the pySetupReg registrar function.
#!../../bin/linux-x86_64/softIocPy2.7
# Interpreter not started
dbLoadDatabase("../../dbd/softIocPy.dbd",0,0)
softIocPy_registerRecordDeviceDriver(pdbbase)
# Interpreter started
An epicsAtExit cleanup handler is also registered at this time.
Several IOC Shell functions are also registered. py() executes a line of python code. pyfile() reads and interprets a python script.
py("import mymod;)
py("mymod.makeDev('one')")
py("mymod.makeDev('two')")
pyfile("myinit.py")
PYTHONPATH¶
The interpreter search path is automatically prefixed with the following additional paths:
${PWD}
$(TOP)/python<PY_VER>/$(EPICS_ARCH)
$(PYDEV_BASE)/python<PY_VER>/$(EPICS_ARCH)
$(EPICS_BASE)/python<PY_VER>/$(EPICS_ARCH)
The environment variables EPICS_BASE
, PYDEV_BASE
, TOP
, and EPICS_ARCH
will be used if set. Compile time defaults are selected for
EPICS_BASE
, PYDEV_BASE
, EPICS_ARCH
.
If TOP
is not set then the this entry is omitted.
The default for PYDEV_BASE
is the $(INSTALL_LOCATION)
given when the
pyDevSup module was built.
Build Environment¶
When building IOCs or installing files, include PYDEVSUP
in your configure/RELEASE
file.
PYDEVSUP=/dir/where/pyDevSup/is/installed
EPICS_BASE=/....
The default or preferred Python version can be specificed in configure/CONFIG_SITE
PY_VER ?= 2.7
The following should be added to individual EPICS Makefiles.
TOP=../..
include $(TOP)/configure/CONFIG
include $(PYDEVSUP)/configure/CONFIG_PY
...
include $(TOP)/configure/RULES
include $(PYDEVSUP)/configure/RULES_PY
This will add or amend several make variables. The USR_*FLAGS
variables
may be extended with appropriate flags for building python modules. The PY_VER
variable is defined with the Python version number found in install directories (eg “2.7”).
The PY_LD_VER
variable is defined with the python library version number (eg “3.2mu”),
which may be the same as PY_VER
.
Include pyDevSup in your IOC¶
While the softIocPyX.Y executable(s) built as part of this module will be sufficient for many uses, it is also possible to include the pyDevSup modules in an IOC along with other drivers. This can be done in the usual way.
PROD_IOC = myioc
DBD += myioc.dbd
...
myioc_DBD += pyDevSup.dbd
...
myioc_LIBS += pyDevSup$(PY_LD_VER)
Installing .py files¶
Additional .py files can be installed as follows.
PY += mymod/__init__.py
PY += mymod/file1.py
Building extensions¶
For convenience, additional Python extensions can be build by the EPICS build system. In this example the extension name is “_myextname” and the resulting library is expected to provide the an initialization function named “init_myextname”.
LOADABLE_LIBRARY_HOST = _myextname
_myextname_SRCS += somefile.c
In somefile.c
PyMODINIT_FUNC init_myextname(void)
Installing for several Python versions¶
The recipe for building and installing the pyDevSup module for several python version side by side is
make PY_VER=2.6
make clean
make PY_VER=2.7
make clean
make PY_VER=3.2
make clean
The PYTHON
make variable can be specified if the interpreter executable
has a name other than python$(PY_VER)
.