RE: [Python-Dev] Placement of os.fdopen functionality

[Greg Ewing]

Hmmm, I wasn't sure whether fileno() was a required part of stdio, or whether it only existed on unix-like systems. If it really is required, I guess it doesn't have to be in the os module.

It's not required by standard C -- standard C has only streams, not file descriptors. Nevertheless, POSIX requires them, and uses of fileno() in Python are unconditional (aren't conditionally compiled depending on config symbols), so they're on every platform Python links on today.