Alexey Izbyshev added the comment:
Yes, despite that MSVCRT knows the type of the file descriptor because it calls
GetFileType() on its creation, it doesn't check it in lseek() implementation
and simply calls SetFilePointer(), which spuriously succeeds for pipes. MSDN
says the following[1]:
New submission from Myungbae Son :
>>> import os
>>> r, w = os.pipe()
>>> os.lseek(w, 10, 0)
10
>>> wf = open(w, 'w')
>>> wf.seekable()
True
This happens on Windows. Consequently seek() works for these objects but they
seems to be no-op. This may confuse libraries that depend on seeking.
The
