Python -v import behavior

[M.-A. Lemburg]

On 2008-04-30 18:42, Sean Ryan wrote:
> Hi all,
> (A similar question was posted by a colleague, but did not appear to  reach
> comp.lang.python or this list).
> 
> I am wondering if the -v option causes the python application to be more
> tolerant to module import warnings and / or errors.
> 
> The reason is that a module is failing to import correctly (generating an
> ImportError exception).  Examining this closer we re-ran the script using
> the -v option. to find that "Unsatisfied symbol" errors we being displayed
> during import (cx_Oracle 4.3.1, python 2.5.1, HP-UX 11, oracle 9.2).
> However, the module is usable from the python prompt (when using -v)
> displayed, i.e. dir (cx_Oracle) works correctly, as does  database
> interaction.  Without the -v option the script is halted due to the
> ImportError exception.
> 
> My questions are:
> 1.  Is there a way to mimic the seemingly more tolerant import behavior  of
> python -v without producing the verbose output ?
> 2.  Is the behavior described above expected and documented ?

The -v option only causes Python to print more information to
stderr explaining where it is looking for modules.

You should be seeing any dynamic loader messages in both cases,
ie. when running with or without -v.

While it is possible that cx_Oracle does some extra processing
when running Python in -v mode, this is rather unlikely.

Note that the best way to track down "unsatified symbol" errors
is to inspect the dependencies of the modules and other shared
libs involved.

Running an strace (or similar system trace utility) will also
help to identify the problem, since this lists the shared libs
the process tries to load when starting up and also during
import of Python modules.

-- 
Marc-Andre Lemburg
eGenix.com

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