__file__ variable not available in module init

[robertwb]

test.pyx

try:
    print __file__
except NameError, ex:
    print "Got name error."

def get_file():
    return __file__

>>> import test
Got name error.
>>> test.get_file()
'test.so'

Migrated from http://trac.cython.org/ticket/475

[robertwb]

@robertwb changed description from

----------- test.pyx ----------

try:
    print __file__
except NameError, ex:
    print "Got name error."

def get_file():
    return __file__

---------------------------------

>>> import test
Got name error.
>>> test.get_file()
'test.so'

to

test.pyx

try:
    print __file__
except NameError, ex:
    print "Got name error."

def get_file():
    return __file__

>>> import test
Got name error.
>>> test.get_file()
'test.so'

commented

[robertwb]

bfroehle changed cc to bfroehle
commented

As far as I know it's technically impossible to access __file__ when the module is being imported.

Regular Python modules are run with a dictionary which has been which has been pre-initialized with some values (__file__, __builtins__).

On the other hand, extension modules (like what Cython produces) have their init function run and then have the __file__ attribute set. (See Python/importdl.c).

Since this cannot be fixed, I guess it should be documented and closed.

[robertwb]

scoder commented

See http://bugs.python.org/issue13429

[scoder]

Fixed with Py3.5 (PEP 489) in #1715.