On 27/04/2012 6:55 PM, Stefan Behnel wrote:
Peter Faulks, 27.04.2012 10:36:
On 27/04/2012 5:15 PM, Stefan Behnel wrote:
Peter Faulks, 26.04.2012 19:57:
I want to extend an embedded interpreter so that calls to print() are
automagically sent to a C++ gui (windows exe) via a callback function in
the DLL.
Then I'll be able to do this:
----test.py----
import printoverload
printoverload.set_stdout()
printoverload.set_stderr()
print("this will be sent to a C function in printoverload.pyd")
---------------
Why would you want to divert only "print" instead of changing sys.stdout in
general? Not all output comes from print calls.
Because I don't want to have to poll the stdout buffer.
You don't have to. It's delivered right at your door and even rings the
bell when it arrives to hand over the parcel in person.
I want the script
itself to update a window in the host application (via the extension) every
time the script calls print().
Then replace sys.stdout (and maybe also sys.stderr) by another object that
does what you want whenever its write() method is called.
But I guess that won't work if the script raises an exception...
Yep, you better catch those yourself. The C-API function you use for
executing the Python code in the first place will tell you when there was
an error.
BTW, my mention of Cython wasn't just a joke. You might want to look at it
because it makes these things essentially trivial compared to plain C-API
code in C.
Stefan
OK, I _think_ I'm getting warmer... But I wonder, do I need to create
new sys.stdout / sys.stderr objects? Can I not simply assign a custom C
function to the write() methods of the existing sys.stdout / sys.stderr
objects?
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