Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!uwm.edu!zaphod.mps.ohio-state.edu!pacific.mps.ohio-state.edu!linac!unixhub!stanford.edu!agate!usenet.ins.cwru.edu!tut.cis.ohio-state.edu!uoft02.utoledo.edu!desire.wright.edu!jmatthews
From: jmatthews@desire.wright.edu
Newsgroups: comp.sys.mac.programmer
Subject: Re: SerialDriver programming
Message-ID: <1991Apr9.230956.3159@desire.wright.edu>
Date: 10 Apr 91 04:09:56 GMT
References: <1991Apr9.002744.28880@wpi.WPI.EDU>
Organization: University Computing Services, Wright State University
Lines: 43

In article <1991Apr9.002744.28880@wpi.WPI.EDU>, nuk@wpi.WPI.ED
(Jacob W Anderson) writes:
> I have been trying to program my serial port on a MacSE with 128k ROMs using
> a Hayes compatible modem, but have found that the protocol used in the
> following program does not work properly.  In fact, it does not work at all
> it does not generate any run-time errors, but rather does nothing that it
> should (like dialing).
> Please, if you have any idea what I am doing wrong, please tell me.  I possible
> please tell me in 'C' for I am using both Think Pascal and Think C, but the
> final project is to be in 'C'.  Thanks in adavance.
>  
>                         please E-mail.
>                         nuk@wpi.wpi.edu
>  
> ================================================
>  
> [...]
> 
>         {this procedure sends data to the modem}
>         procedure Send (Data: Str255);
>                 var
>                         Count: LongInt;
>         begin
>                 Count := LongInt(Length(Data));
>                 writeln('Sending ', Data, ' &', count, 'bytes');
>                 Buffer := @Data;
>                 Error := FSWrite(PortOut, count, Buffer);
>                 DoError;
>         end;
>  
> [...]

One problem lies in passing FSWrite a pointer to the first byte in a Pascal
string. This byte is the string's length. Try

	Buffer:= pointer(ord(@data)+1)

Hope this helps, John

o----------------------------------------------------------------------------o
| John B. Matthews, jmatthews@desire.wright.edu, am103@cleveland.freenet.edu |
| "Say...what's a mountain goat doing way up here in a cloud bank?" - Larson |
o----------------------------------------------------------------------------o