[Gambas-user] To fast do..loops for process management!

[Demosthenes Koptsis]

Hi dear list,

I write a front-end for mpg123 mp3 console player in gambas2 but i
came face to face with a bug and i need your help!
i dont know if the bug is due to gambas or my writing code or mpg123 player's.

The story is like this....

'### I have two public vars

PUBLIC hProcess AS Process 'varProcess is a Process variable for SHELL command
PUBLIC iNrPlayingSong AS Integer 'public var to hold the nr of playing song

'### i execute a command to play mp3 songs

.....
    'format sting command
    sCommand = "mpg123 -vC@ " & sPlaylistFile 'play in verbose mode
(v), interactive (C), and load a playlist (@)
    'execute command
    hProcess = SHELL sCommand FOR INPUT OUTPUT
.....


'### previous track sub
PUBLIC SUB btnPreviousTrack_Click()

    IF NOT IsNull(hProcess) THEN
      IF hProcess.State = 1 THEN PRINT #hProcess, "d"  'mpg123 recieve
a keyboard "d" to go previous track
    ENDIF

END


'### next track sub
PUBLIC SUB btnNextTrack_Click()

  IF NOT IsNull(hProcess) THEN
    IF hProcess.State = 1 THEN PRINT #hProcess, "f"   'mpg123 recieve
a keyboard "f" to go next track
  ENDIF

END

'### NOTE, the previous SUBs are the same. They differ only to letters
"f" and "d"


'#### A wait sub for the system, see next!
PUBLIC SUB WaitSystem()

  'wait the system
  FMain.Mouse = 3
  WAIT 0.05
  FMain.Mouse = 0

END



'########### So far with no bug, the code is working



'### i write a sub if user click in playlist a list item = a mp3 track

PUBLIC SUB lvwPlayList_DblClick()

  DIM iCounter AS Integer = iNrPlayingSong 'var get current playing
song and also act as counter. iNrPlayingSong get its value from SUB
Process_Read()

  IF NOT IsNull(lvwPlayList.Key) THEN
	
'### This do..loop part working fine
	'if user click an item with key greater than number of playing song
    IF (lvwPlayList.key + 1) > iCounter THEN 'go next track
       DO
          IF iCounter = (lvwPlayList.key + 1) THEN BREAK
          'PRINT "Go next track"
          btnNextTrack_Click()
          INC iCounter
       LOOP
    ENDIF

	'if user click an item with key smaller than number of playing song
    IF (lvwPlayList.key + 1) < iCounter THEN 'go previous track
       DO
          IF iCounter = (lvwPlayList.key + 1) THEN BREAK
          'PRINT "Go previous track"
          btnPreviousTrack_Click()

	  ' ### Now the strange bug
          '!FIXEME!
####################################################################################
          WaitSystem() '***!!!!!***---> ### [ -- i need to force a
wait system sub to working correctly --- ]
          'Probably there is a bug.
	  'the hProcess does not recieve the btnPreviousTrack_Click() command
as recieves btnNextTrack_Click()

          'The same code in btnNextTrack_Click() works fine.
          'Sorry for the annoying bug.
          '!FIXEME!
####################################################################################

          DEC iCounter

       LOOP
    ENDIF

  ENDIF

END

'####################

To test this bug make a long playlist with up to 200 mp3s.

if you check the two subs btnNextTrack_Click() and
btnPreviousTrack_Click() are the same.
If you check the two DO..LOOPs parts are the same, they only change in
btnNextTrack_Click() and btnPreviousTrack_Click().
In first case the btnNextTrack_Click() works.
In second case i need to force a wait to application to work the
btnPreviousTrack_Click().

I test to PRINT the vars which they be read from Sub Read_Process and
they are ok. Vars iNrPlayingSong, iCounter are OK.
My conclusion is that hProcess cannot recieve so quickly the previous
command from gambas2.
So the questions now!
Is this a bug of mpg123 player or a bug of gambas in process management?


I attach my project if you want to look its strange bug.

--

Γεια χαρα σε όλους!!!

Regards,

Demosthenes Koptsis
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