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:

Thu, 7 Sep 2006 20:57:16 -0400

Message-ID:

<u2Y17Gu0GHA.4580@TK2MSFTNGP05.phx.gbl>

"sleeper" <TheFakeJon@gmail.com> wrote in message
news:1157675231.843961.230340@i3g2000cwc.googlegroups.com...

The problem I am having is that within my DLL, when the call back
function gets called, I would like to write the key that got pushed
into a text file. so within KeyboardProc(..), I created an ofstream
and determined which key got pushed, and write that to the file.
Unfortunately, this is not working. I am wondering if there is
something that I am missing.

Well, you don't say how it is not working. You must remember that everything
that you do inside a hook is done in the context of the process being
hooked. If you open the file, write and close it inside the hook procedure
it should work. But you can't expect to open a file in one executable and
write to it from another unless that executable has opened the file.

Of course, you need to be careful about negatively impacted performance with
a hook. You might want to think of ways of pushing that character out to
your executable (the one which planted the hook) and have it do the file
I/O.

Regards,
Will