In the discussion on "select bug", some people noted that select does not
wake up a process until the buffer is half full (or all full, or
whatever). Does this mean that if a small amount is written to the
device/pipe the process may never be woken? Or is there a time limit that
wakes up the process after a certain amount of time if there are _any_
bytes in the pipe/dev?
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David Feuer
[email protected]
On Sun, Nov 05, 2000 at 01:46:19AM -0500, David Feuer wrote:
> In the discussion on "select bug", some people noted that select does not
> wake up a process until the buffer is half full (or all full, or
> whatever). Does this mean that if a small amount is written to the
> device/pipe the process may never be woken? Or is there a time limit that
> wakes up the process after a certain amount of time if there are _any_
> bytes in the pipe/dev?
This only applies to POLLOUT. Yes, if an send buffer stays 90%
full forever you may be never woken up.
In case of a TCP socket you would be at worst waken up after considerable
time with a ETIMEDOUT.
Pipes do not signal writable until the pipe is empty.
-Andi
> wake up a process until the buffer is half full (or all full, or
> whatever). Does this mean that if a small amount is written to the
Writer not reader