Totally missed this reply for some reason . ..
-----Original Message-----
From: Ed W [mailto:[EMAIL PROTECTED]
Sent: Saturday, June 16, 2007 11:54 AM
To: Ovod-Everett, Toby
Cc: wxperl-users
Subject: Re: [wxperl-users] grr, vista issues
> No, I wrote the app, so I don't think it buffers its output (or if it
> does then it can be changed)
If it's using STDIO, it buffers by default as soon as STDIO discovers
that the output device isn't a console but is a file or STDIN of another
program. Thus $| in Perl (which should be set to 1 for handles where
you want to ensure that they do not buffer). Thus the common idiom:
select((select(MYHDL), $|=1)[0]);
> I had considered running the program via shellexecute, spooling the
> output to a file and reading in the file. Seemed quite ugly though...
> I hadn't really given it much more thought, but why would I need a
> wrapper around the shellexecute? Does it turn out to be difficult to
> start that up with output redirected to a file?
Capturing output is a weird business, having to do with all sorts of
weird plumbing stuff in NT that I don't completely understand. I don't
think ShellExecute lets you specify STDIO handles - that's a Microsoft
decision. See http://msdn2.microsoft.com/en-us/library/ms647732.aspx
and http://msdn2.microsoft.com/en-us/library/ms682425.aspx and see if
you can find the equivalent of the STARTUPINFO structure (one of the
options to CreateProcess) for ShellExecute - I don't see it. The
STARTUPINFO structure includes hStdInput, hStdOutput, and hStdError,
which is, I presume, how Perl goes about capturing output (by creating a
handle and passing it in STARTUPINFO).
Given all of that, I think you're going to have to use some program to
capture the output. Whether that program is $ENV{COMSPEC} using ">" to
redirect it to a file or whether it's a custom Perl program that uses
named pipes or something like that to communicate back to its "host", I
think that's the route you're going to have to follow.
--Toby Ovod-Everett
-----Original Message-----
From: Ed W [mailto:[EMAIL PROTECTED]
Sent: Saturday, June 16, 2007 11:54 AM
To: Ovod-Everett, Toby
Cc: wxperl-users
Subject: Re: [wxperl-users] grr, vista issues
Hi
> Does the "small C based installer app" use buffering on its pipes or
> not? If not, is there a way to write another small C (or
PerlApp-based)
> wrapper that is also marked as needing elevated permissions that will
> then start the installer app and redirect its output to a temp file
that
> can then be read by the Wx app?
>
No, I wrote the app, so I don't think it buffers its output (or if it
does then it can be changed)
I had considered running the program via shellexecute, spooling the
output to a file and reading in the file. Seemed quite ugly though...
I hadn't really given it much more thought, but why would I need a
wrapper around the shellexecute? Does it turn out to be difficult to
start that up with output redirected to a file?
Cheers
Ed W
