[TCLCORE] Why TclUnixWaitForFile ?

[Alexandre F. <ale...@gm...>]

Hi,

While reviewing [patch 1960647]  Add ability to use poll() in
TclUnixWaitForFile()
https://sourceforge.net/tracker/index.php?func=detail&aid=1960647&group_id=10894&atid=310894

I discovered the existence of this strange function. Can somebody give
me the rationale for it ?

Its clear and documented effect is to resynchronize the async
connection of a socket prior to honoring an I/O request on the socket.
What I don't understand is:

 (a) why resync in that case, instead of just throwing an error "not
yet connected", relying on the caller to use the event loop as usual
to detect the completion of the connect phase ? (I know it's way too
late to change, I just want to understand)

 (b) why is it unix-specific ?

TIA,

-Alex