Hi,

I am trying to debug an old problem with CsoundQt that sensekey does not work when used within CsoundQt, see
https://sourceforge.net/p/csound/mailman/csound-users/thread/55BFA6CF.9070903@joachimheintz.de/

In fact it does, if to start CsoundQt binary from terminal or QtCreator or  even if to click on it  in file manager (Linux).

But if to start the program via a desktop file (like from start menu), it does not -  the sensekey.csd example from manual returns error:

PERF ERROR in instr 1: read failure in sensekey

k1 k2 sensekey

note aborted

CsoundQt catches the keyboard events correctly and forwards them to Csound API via csoundRegisterKeyboardCallback:

csoundRegisterKeyboardCallback(ud->csound,  &CsoundEngine::keyEventCallback,
                                   (void *) ud, CSOUND_CALLBACK_KBD_EVENT | CSOUND_CALLBACK_KBD_TEXT);

I tested that the key is correctly there in CsoundQt side but the problem happens somehow in between or in Csound. The callback fuction in CsoundQt is (csoundengine.cpp:401-427) :

int CsoundEngine::keyEventCallback(void *userData,
                                   void *p,
                                   unsigned int type)
{
    if (type != CSOUND_CALLBACK_KBD_EVENT && type != CSOUND_CALLBACK_KBD_TEXT) {
        return 1;
    }
    CsoundUserData *ud = (CsoundUserData *) userData;
    //  WidgetLayout *wl = (WidgetLayout *) ud->wl;
    int *value = (int *) p;
    int key = ud->csEngine->popKeyPressEvent();
    QString command = "oscsend localhost 9990 /keyEventCallback i " + QString::number(key);
    if (key!=-1)
        system(command.toLocal8Bit() ); // FOR TESTING
    if (key >= 0) {
        *value = key;
//            qDebug() << "Pressed: " << key;
    }
    else if (type & CSOUND_CALLBACK_KBD_EVENT) {
        key = ud->csEngine->popKeyReleaseEvent();
        if (key >= 0) {
            *value = key | 0x10000;
            //       qDebug() << "Released: " << key;
        }
    }
    return 0;
}

From the sent OSC message (since I cannot test it in terminal) I can see, that key value is correct  here before the sensekey error happens.

I found the part in Csound code that is responsible for that is in Oops/bus.c function sensekey_perf (line 1298- ). I must say I don't understand it completely. Can you help me further, is there anything I can do from Qt side to make the connetion work?

As I undertstand correctly, the error detected here (l. 1334-)

 retval = select(1, &rfds, NULL, NULL, &tv);

        if (retval) {
          char    ch = '\0';
          if (UNLIKELY(read(0, &ch, 1)!=1)) {
            csound->PerfError(csound, p->h.insdshead,
                              Str("read failure in sensekey\n"));
            return NOTOK;
          }
          keyCode = (int)((unsigned char) ch);
          /* FD_ISSET(0, &rfds) will be true. */
        }

i.e. ' read(0, &ch, 1)' fails. Do I read correctly that it tries to read one byte from file/FIFO 0 (probably standard input) to vairable 'ch'? How does the callback function send its informatio to there?  What does the select() line above do?

I hope you can enlighten me and give some hints, what to try out.

Thanks!

tarmo

On Fri, 26 Feb 2016, Tarmo Johannes wrote:

> 
> As I undertstand correctly, the error detected here (l. 1334-)
> 
>  retval = select(1, &rfds, NULL, NULL, &tv);
> 
>         if (retval) {
>           char    ch = '\0';
>           if (UNLIKELY(read(0, &ch, 1)!=1)) {
>             csound->PerfError(csound, p->h.insdshead,
>                               Str("read failure in sensekey\n"));
>             return NOTOK;
>           }
>           keyCode = (int)((unsigned char) ch);
>           /* FD_ISSET(0, &rfds) will be true. */
>         }
> 
> i.e. ' read(0, &ch, 1)' fails. Do I read correctly that it tries to read one
> byte from file/FIFO 0 (probably standard input) to vairable 'ch'? How does the
> callback function send its informatio to there?  What does the select() line
> above do?
>

On the other hand the code before that says
         FD_ZERO(&rfds);
         FD_SET(0, &rfds);
         /* No waiting */
         tv.tv_sec = 0;
         tv.tv_usec = 0;

         retval = select(1, &rfds, NULL, NULL, &tv);

so it looks too see if there is a character waiting on fd 0 immediately.
This code is MACH and unix only by the way
==John

Ps that would be better read as
.....
  if (retval>0) {
......

which would ignore errors.  Will adjust the  code now

I have not found a way of getting key information on GNU/Linux and this 
code looks right.  If fd 0 does not exist I cannot see ow it can be 
reported as ready to read.
   There is a cryptic remark in the man page for select that suggests a fd 
at EOF could be reported as ready.  I suppose one could persue that idea? 
I will look at further code changes


On Fri, 26 Feb 2016, Tarmo Johannes wrote:

> Thanks,
> 
> pulled from git and tested but that does not solve the problem.
> Seems that stdin is not available when the program is not started from
> terminal.
> 
> Is there something to do? I tried to add  <&0  behind the execution command in
> destop file:
> 
> [Desktop Entry]
> Exec=bash -c/home/tarmo/src/qutecsound/build-qcs-Qt5_desktop-Debug/bin/CsoundQt-d-py-cs6-
> debug  %F <&0
> 
> but it did not work.  I don't understand the piping or redirections so well,
> too....
> 
> And it still it puzzles me - CsoundQt has the key info, keyboard callback is
> set, but the info gets lost.
> How does csoundRegisterKeyboardCallback work and how can the key event arrive
> into stdin that sensekey is reading exlusively?
> 
> Can this be also  it a timing issue?
> 
> One way is of course to start CsoundQt always from terminal but this does not
> seem so neat...
> 
> 
> Thanks!
> 
> tarmo
> 
> 2016-02-26 18:19 GMT+02:00 jpff :
>       Ps that would be better read as
>       .....
>        if (retval>0) {
>       ......
>
>       which would ignore errors.  Will adjust the  code now
>       ==Jon
> 
> 
> 
>

I added code to handle EOF

Hi,

Just for information I am reporting back that I solved the issue in CsoundQt by sending a dummy keypress to Csound right after registering the keyboard Callback:

#ifdef CSOUND6

csoundRegisterKeyboardCallback(ud->csound, &CsoundEngine::keyEventCallback, (void *) ud, CSOUND_CALLBACK_KBD_EVENT | CSOUND_CALLBACK_KBD_TEXT);

csoundKeyPress(getCsound(),'\0'); // necessary to put something into the buffer, otherwise sensekey complains when not started from terminal

#else

...

Now sensekey works as expected also when the program is not started from terminal.

Looking again at the sensekey code in bus.c, is'nt it so that if a callback is set, the conditions should be so that the function should not check for stdin at all? Probably I am still not understanding the code completely.

Anyway, it is fine now with that matter.

Thanks!

tarmo

On Friday 26 February 2016 17:44:34 you wrote:

> I added code to handle EOF

> Not sure this is the answer but it is better