Re: Writing to a file within a Call Back Function

From:
"William DePalo [MVP VC++]" <willd.no.spam@mvps.org>
Newsgroups:
microsoft.public.vc.mfc,microsoft.public.vc.language
Date:
Fri, 8 Sep 2006 12:30:12 -0400
Message-ID:
<#8cHQQ20GHA.480@TK2MSFTNGP06.phx.gbl>
"sleeper" <TheFakeJon@gmail.com> wrote in message
news:1157684075.252535.208550@m73g2000cwd.googlegroups.com...

oh, well I wanted to learn how hooks work in Windows, so I decided that
the easiest way is to create a hooking procedure that logged keys. I
guess I could have done a slew of other projects...


OK. If this is an experiment or a learning exercise you are free to do
whatever you like. :-)

In a shipping application you should think very carefully about implementing
a system-wide hook, especially one which does I/O on every key stroke.

so conceptually, I want my hook to be minimally as intrusive, so if I
create a shared memory buffer between the two, this should still be
fine right?


Well, yes. Copying a keystroke to memory is a lot less expensive than an I/O
operation.

How about a pipe? I think pipes would be relatively easy
to implement...


Yup. In fact, CallNamedPipe() dumbs down the client side of the pipe to a
single line. But it is not going to return until the message has received a
reply. IMO, this is not the kind of thing that you should be doing inside a
hook procedure.

Regards,
Will

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