Question

I just noticed that my old codes written in python 2.5 does not work now. I am in python 2.6 btw.

>>> os.spawnl(os.P_NOWAIT,"setup.exe")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "c:python26libos.py", line 612, in spawnl
    return spawnv(mode, file, args)
OSError: [Errno 22] Invalid argument
>>>

Any clue? or do you have any working sample of os.spawn* with NOWAIT option.

Update:

Even I put full path in os.spawnl(), Its still error.

Answer 1

thrope is right about subprocess being preferred. But the spawn* stuff is still there in 2.6. In fact, you can see that in your error message. Your first arg seems to be valid. I d check the second arg, which is the path.

Answer 2

I got it work by adding DUMMY parameter finally, a bit funky though

This is not working

os.spawnl(os.P_NOWAIT,"Setup.exe")

This is also not working

os.spawnl(os.P_NOWAIT,"Setup.exe","")

But this is working

os.spawnl(os.P_NOWAIT,"Setup.exe","DUMMY")

Thanks all anyway.

Answer 3

I think its recommended to use the subprocess module these days rather than the os.spawn* functions. (I can t reproduce your problem, but I m not on windows).

Answer 4

A Google search brings up this page about the same problem happening when there is a space in the Python installation path. I couldn t reproduce it here, but maybe it s the problem?

In any case, according to MS documentation this error value (EINVAL) should only be returned if the mode argument is invalid, which isn t the case here.

Answer 5

os.spawnl() requires full path to executable, while os.spawnlp() uses PATH environment variable to find it.

Update: Also it s common error to use unescaped backslashes in the path literal (try printing it to see whether it s interpreted right).

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