sys.stderr and PyErr_WriteUnraisable

[Jan Langer]

Gabriel Genellina schrieb:
> En Tue, 15 Dec 2009 11:17:20 -0300, Jan Langer 
> <jan.langer at etit.tu-chemnitz.de> escribió:
> 
>> from test.test_support import captured_output
>> with captured_output("stderr") as stderr:
>>      def g():
>>          try:
>>              g()
>>          except RuntimeError,e:
>>              pass
>>      g()
>>      print stderr.getvalue()
>>
>> I expect the ignored exceptions to be printed into the StringIO object 
>> stderr. With this code there are no warnings on the command line, but 
>> getvalue() returns nothing.
> 
> If sys.stderr is not a real file, no error gets printed.
> PyErr_WriteUnraisable calls PyFile_WriteString, which checks for 
> non-file objects and only writes to them when no error is set.
> Seems to be a safety measure.
> 

thanks for the quick answer. PyErr_WriteUnraisable calls PyErr_Fetch 
first, which should clear the error indicator, and the PyErr_Occurred in 
PyFile_WriteString should return false.