A very big "thanks" to all those who looked into this issue, and especially to Joachim, who found the solution. Indeed, I changed a1 to a2 in poscil and everthing is all right also for me. There is probably a small bug lurking in the code of poscil, but, as far as I'm concerned, I can just use two variables.
Thanks again.

Marco


----- Ursprüngliche Mail ----
> Von: joachim heintz 
> An: csound@lists.bath.ac.uk
> Gesendet: Dienstag, den 12. August 2008, 16:21:06 Uhr
> Betreff: [Csnd] Re: To oscili or not to poscil...
> 
> I don't know why, but the reason seems to be the same variable name  
> (a1) for both the envelope and the audio signal. I tried it (MacBook  
> 10.4.11, Csound 5.08), and it was the same as you describe. But when  
> writing
>           a1    oscili  isin_amp, idurosc, islowenv
>           a2    poscil  a1, if0, iaudiofun
>         out a2
> everything is ok.
> Perhaps someone  can have a look in the source code of poscil. There  
> seems to be a problem if an argument name is the same as the output  
> variable.
> Best -
>     joachim
> 
> 
> 
> Am 11.08.2008 um 17:42 schrieb Marco Stroppa:
> 
> > Hello!
> >
> > The two simple orchestras below use one oscili, the other poscil,  
> > which will have a better precision. Oddly enough, on my computer  
> > (PowerMac, OSX 10.5.4, running csound-intel 5.08), the former  
> > produces a nice bell-like sound, while the latter (with the same  
> > score) a click (only the amplitude envelope, no sound whatsoever).
> > Do you experience the same behaviour? Is it a problem of my  
> > computer, of this version of csound, or have I simply been working  
> > too... long?
> > Thanks for any advice.
> >
> >
> > Marco
> >
> > ; TEST OSCILI
> > sr= 96000
> > kr= 96000
> > ksmps= 1
> > nchnls= 1
> >
> > 0dbfs = 8388697 ; 24 bits
> >
> > instr 1;  
> > --------------------------------------------------------------------
> >
> > idur=  p3
> > idurosc= 1/idur
> > isin_amp= (p4 > 0.0 ? (p4*0dbfs) : (ampdbfs (p4)))
> > if0=  p5
> >
> > iaudiofun=  1
> > islowenv=  2
> >
> > ; sine tone
> >          a1     oscili  isin_amp, idurosc, islowenv
> >          a1     oscili  a1, if0, iaudiofun
> >
> >                 out     a1
> > endin
> >
> >
> >
> > ; TEST POSCIL
> > sr= 96000
> > kr= 96000
> > ksmps= 1
> > nchnls= 1
> >
> > 0dbfs = 8388697 ; 24 bits
> >
> > instr 1;  
> > --------------------------------------------------------------------
> >
> > idur=  p3
> > idurosc= 1/idur
> > isin_amp= (p4 > 0.0 ? (p4*0dbfs) : (ampdbfs (p4)))
> > if0=  p5
> >
> > iaudiofun=  1
> > islowenv=  2
> >
> > ; sine tone
> >          a1     oscili  isin_amp, idurosc, islowenv
> >          a1     poscil  a1, if0, iaudiofun
> >
> >                 out     a1
> > endin
> >
> >
> > ;SCORE
> > ; GEN functions  
> > **********************************************************
> > ; waveform
> > f1  0  8193  9  10  1  0  16  1  0  22  1  0  23  1  0
> >
> > ; envelope
> > f2  0  513  5   256  512  1
> > ;End of Instrument's Header
> >
> > i1 0.0 5.0 -6.0 100.0
> >
> >
> > __________________________________________________
> > Do You Yahoo!?
> > Sie sind Spam leid? Yahoo! Mail verfügt über einen herausragenden  
> > Schutz gegen Massenmails.
> > http://mail.yahoo.com
> >
> >
> > Send bugs reports to this list.
> > To unsubscribe, send email sympa@lists.bath.ac.uk with body  
> > "unsubscribe csound"
> 
> 
> 
> Send bugs reports to this list.
> To unsubscribe, send email sympa@lists.bath.ac.uk with body "unsubscribe csound"


__________________________________________________
Do You Yahoo!?
Sie sind Spam leid? Yahoo! Mail verfügt über einen herausragenden Schutz gegen Massenmails. 
http://mail.yahoo.com