[Interest] Redirect stdout to a file

william.crocker at analog.com william.crocker at analog.com
Tue Jul 2 15:59:27 CEST 2013


Do you have control over the child program, here?
Do you have the source code?
Are you willing to change it?

Bill

On 07/02/2013 09:54 AM, Yifei Li wrote:
> Hi Scott,
>
> I'm working on a Mac. How about you? OS probably matters.
>
> Yifei
>
>
> On Mon, Jul 1, 2013 at 11:30 PM, Scott Aron Bloom <scott.bloom at onshorecs.com
> <mailto:scott.bloom at onshorecs.com>> wrote:
>
>     Yes that is exactly what I do.. ____
>
>     __ __
>
>     *From:*Yifei Li [mailto:yifli82 at gmail.com <mailto:yifli82 at gmail.com>]
>     *Sent:* Monday, July 1, 2013 7:29 PM
>
>
>     *To:* Scott Aron Bloom
>     *Cc:* interest at qt-project.org <mailto:interest at qt-project.org>
>     *Subject:* Re: [Interest] Redirect stdout to a file____
>
>     __ __
>
>     Hi Scott,____
>
>     __ __
>
>     What I'm trying to do is exactly the same as what you did. ____
>
>     __ __
>
>     Can you confirm the following is how you made it? In my experiment, the
>     following way makes the newly created process terminate when the GUI
>     crashes. ____
>
>     __ __
>
>     QProcess *proc = new QProcess;____
>
>     connect(proc, SIGNAL(readyReadStandardError()), this SLOT(readStderr()));____
>
>     proc->start();____
>
>     __ __
>
>     Thanks,____
>
>     __ __
>
>     Yifei____
>
>     __ __
>
>     On Mon, Jul 1, 2013 at 6:28 PM, Scott Aron Bloom <scott.bloom at onshorecs.com
>     <mailto:scott.bloom at onshorecs.com>> wrote:____
>
>         Im completely confused on what you are trying to do..____
>
>         ____
>
>         I can tell you that, I have a QProcess variable, and I have attached to
>         the “stdout/stderr available signals”.. When they trigger, I get the
>         stdout and stderr____
>
>         ____
>
>         And if the GUI crtashes while the CLI call is running, the CLI keeps
>         running.____
>
>
>         Scot____
>
>         ____
>
>         *From:*Yifei Li [mailto:yifli82 at gmail.com <mailto:yifli82 at gmail.com>]
>         *Sent:* Monday, July 01, 2013 3:21 PM____
>
>
>         *To:* Scott Aron Bloom
>         *Cc:* interest at qt-project.org <mailto:interest at qt-project.org>
>         *Subject:* Re: [Interest] Redirect stdout to a file____
>
>         ____
>
>         So is there a way to achieve what I want? -Yifei____
>
>         ____
>
>         On Mon, Jul 1, 2013 at 6:15 PM, Scott Aron Bloom
>         <scott.bloom at onshorecs.com <mailto:scott.bloom at onshorecs.com>> wrote:____
>
>         Yes, calling proc.startDetached still calls the static version____
>
>         ____
>
>         *From:*Yifei Li [mailto:yifli82 at gmail.com <mailto:yifli82 at gmail.com>] ____
>
>         *Sent:* Monday, July 01, 2013 2:53 PM
>         *To:* Scott Aron Bloom____
>
>         *Cc:* interest at qt-project.org <mailto:interest at qt-project.org>____
>
>
>         *Subject:* Re: [Interest] Redirect stdout to a file____
>
>         ____
>
>         I just tried, and it does not work. Redirection only works if
>         'proc->start()'. -Yifei____
>
>         ____
>
>         On Mon, Jul 1, 2013 at 5:39 PM, Scott Aron Bloom
>         <scott.bloom at onshorecs.com <mailto:scott.bloom at onshorecs.com>> wrote:____
>
>         Yes… ____
>
>         ____
>
>         ____
>
>         ____
>
>         *From:*interest-bounces+scott.bloom=onshorecs.com at qt-project.org
>         <mailto:onshorecs.com at qt-project.org>
>         [mailto:interest-bounces+scott.bloom
>         <mailto:interest-bounces%2Bscott.bloom>=onshorecs.com at qt-project.org
>         <mailto:onshorecs.com at qt-project.org>] *On Behalf Of *Yifei Li
>         *Sent:* Monday, July 01, 2013 2:25 PM____
>
>
>         *To:* interest at qt-project.org <mailto:interest at qt-project.org>
>         *Subject:* Re: [Interest] Redirect stdout to a file____
>
>         ____
>
>         Hi Scott,____
>
>         ____
>
>         Are you suggesting something as follows? ____
>
>         QProcess proc;____
>
>         proc.setStandardOutputFile();____
>
>         proc.startDetached();____
>
>         ____
>
>         Yifei____
>
>         ____
>
>         ____
>
>         ____
>
>         On Mon, Jul 1, 2013 at 5:08 PM, Scott Aron Bloom
>         <scott.bloom at onshorecs.com <mailto:scott.bloom at onshorecs.com>> wrote:____
>
>         If the goal, is to redirect stdout/stderr, and not have the call block
>         (static startDetached).____
>
>         ____
>
>         You can still use the NON-static version of the start method____
>
>         ____
>
>         Scott____
>
>         ____
>
>         *From:*interest-bounces+scott.bloom=onshorecs.com at qt-project.org
>         <mailto:onshorecs.com at qt-project.org>
>         [mailto:interest-bounces+scott.bloom
>         <mailto:interest-bounces%2Bscott.bloom>=onshorecs.com at qt-project.org
>         <mailto:onshorecs.com at qt-project.org>] *On Behalf Of *Yifei Li
>         *Sent:* Monday, July 01, 2013 1:58 PM
>         *To:* interest at qt-project.org <mailto:interest at qt-project.org>____
>
>
>         *Subject:* Re: [Interest] Redirect stdout to a file____
>
>         ____
>
>         I guess dup2 needs to be called by the process, correct? But I can't
>         change its src code. - Yifei____
>
>         ____
>
>         On Mon, Jul 1, 2013 at 4:42 PM, Guido Seifert <wargand at gmx.de
>         <mailto:wargand at gmx.de>> wrote:____
>
>
>         If it is only Linux you could use dup2.
>
>         Windows? No idea.
>
>         Guido____
>
>
>
>         On Mon, 1 Jul 2013 16:31:19 -0400
>         Yifei Li <yifli82 at gmail.com <mailto:yifli82 at gmail.com>> wrote:
>
>         >  Hi folks,
>         >
>         >  I know this can be done using QProcess::setStandardOutputFile.
>         >
>         >  However, I need to start my process using the static function
>         >  startDetached, and still want to be able to redirect its stdout/stderr to
>         >  another file.
>         >
>         >  Any suggestions?
>         >
>         >  Thanks,
>         >
>         >  Yifei____
>
>         _______________________________________________
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>         Interest at qt-project.org <mailto:Interest at qt-project.org>
>         http://lists.qt-project.org/mailman/listinfo/interest____
>
>         ____
>
>
>         _______________________________________________
>         Interest mailing list
>         Interest at qt-project.org <mailto:Interest at qt-project.org>
>         http://lists.qt-project.org/mailman/listinfo/interest____
>
>         ____
>
>         ____
>
>         ____
>
>
>         _______________________________________________
>         Interest mailing list
>         Interest at qt-project.org <mailto:Interest at qt-project.org>
>         http://lists.qt-project.org/mailman/listinfo/interest____
>
>     __ __
>
>
>
>
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