db4fd99309
The old method only worked out of the box if you were running Python 2.1 on a 586. I imagine that is too small a slice of current users to be worth hard coding ;).
53 lines
2.3 KiB
Text
53 lines
2.3 KiB
Text
** General info on the swig-generated wrappers for Comedilib **
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0) Installing required tools
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The wrapper are made with SWIG. Any of the swig-1.3.x series should
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work. Run
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$ swig -version
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to check the version you have installed, and upgrade if necessary.
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1) Building the wrappers
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Note: the following applies when building wrappers separately from
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the comedilib library, using Python's distutils procedures instead
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of Comedilib's `make`. In this case, Comedilib should be configured
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with the `--disable-python-binding` option to prevent it building
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and installing its own copy of the wrappers.
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After building the main comedilib library (running `make` in the
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base directory), just follow standard distutils procedures
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$ python setup.py build
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$ python setup.py install
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If you want to test the wrappers before installing them, you will
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need to set the `PYTHONPATH` environment variable so Python can find
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the compiled modules. On my system, that looks like
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$ PYTHONPATH=build/lib.linux-i686-2.7/ ../../demo/python/info.py
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2) Using the module
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All the comedilib functions are translated directly to python
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function. The various comedi structs are now available as python
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classes (e.g. comedi_cmd_struct). The members of each struct are now
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attributes of the class and can be set and retrieved in the usual
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way. Comedilib functions which take a pointer to a comedilib struct
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as an argument (in C) now, in python, accept the appropriate struct
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python object.
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For a multichannel acquisition, a C-array containing the channel
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list, gains and referencing is required. This can be created using a
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swig-generated helper class: chanlist(n). This creates a C-array of
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length n and type Unsigned Int. Individual members of the array can
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be accessed/set using pythons indexing syntax:
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mylist = chanlist(3) #creates a chanlist array of length 3
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mylist[0] = 100 #set some values
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mylist[1] = 200
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mylist[2] = 300
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The chanlist object can then be passed to a comedi_cmd_struct
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object, for example. N.B. The chanlist object contains *no*
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length-checking or other error protection so use with care! Don't
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try to get/set indexes outside the array bounds.
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All the comedilib macros (e.g. CR_PACK) are now available as python
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functions (e.g. `comedi.cr_pack`).
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Look at the examples in demo/python to clarify the above.
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