Thank You, Marco, for Your immidiate response!
Show quoted text 20 lines
>I wrote a freePascal program under Linux (Free Pascal Compiler
> version 1.0.10 [2003/06/26] for i386), which reads information from serial
> ports and sends information to serial ports and does some calculations.
> There are no pointers, involved. After the program had run successfully
> for 15 hours, it terminated with the following error message. An
> unhandled exception occurred at 0x08051DC3 : EACCESSVIOLATION : Access
> violation
> 0x08051DC3
> 0x0806ABC0
> 0x080522D8
> 0x080524B8
> 0x08052DE0
> 0x0806F98B
> 0x08130A84
> 0xF2B3E800
> Any idea, what that means?
Access violation. Do you use IOPERM to get access to the ports?
If not, look up ioperm in the manual (under the "linux" unit)
No, I don't use ioperm - and I fear, I don't really understand the description in the manual. But it says there, the program has to be run by root - and I am not happy with that: I don't want to give root privileges to my measurement programs ... .
For port access, I use a routine, that was originally written by Brad Campbell (I got it with one of the older freepascal versions), see below. Is there a reason, better to use IOPerm, ReadPort and WritePort procedures, as stated in the manual? Or is thre just a bug in my port-reading-routine? The error occured (very probably), wile the following routine was in action:
function SerialPort_obj.GetLine(Port : String; BaudRate : LongInt; DataBits : Byte; Parity : Char; StopBits: Byte; FlowControl : String; var TheLine : String) : ShortInt; {Given : - sensorPort, a string with the portname, e.g. '/dev/ttyS1'
- BaudRate, e.g. 9600, compare list of possible values in function SetParameters
- DataBits : 5, 6, 7 or 8
- Parity : 'e', 'o' or 'n' (even, odd or none)
- StopBits : 1 or 2
- FlowControl : 'none' or 'RTSCTS' (Hardware)
- Outstring : String to write to serial port
Task : read line of input from port, referenced by Fd and return it Return : The line of input from Fd.
0 if o.k.
-1 if error occured
}
var
InStr : String[80];
ResStr : String[80];
Quit : Boolean;
InLen, Loop : Integer;
FDs : FDSet;
Is_Error : ShortInt;
Fd : F_Handle;
begin
Is_Error := 0;
ResStr := '';
Quit := False;
Fd := RS232Open(Port); {open port}
if Fd > 0 then Begin
{set the port parameters:}
SetParameters(Fd,BaudRate,DataBits,StopBits,Parity,FlowControl);
FD_Zero (FDs); {Clear File Descriptors Array}
FD_SET (Fd,FDs); {Input from Serial Port}
Repeat { line of input }
Select(Fd+1,@FDS,nil,nil, nil);
If FD_ISSET(Fd,FDS) then {Have we data waiting in UART ? }
Begin
InLen := fdRead(Fd,InStr[1],80);
If InLen > 0 then
For Loop := 1 to Inlen do begin
if ord(InStr[Loop])=13 then quit:=true; {line ended with LF}
if not quit then ResStr := ResStr + InStr[Loop];
end;
end
else begin
writeLn('fatal error in getLine: no line of input from port!');
quit := true;
Is_Error := -1;
end;
Until quit; {Were Outa Here}
FLock(Fd,LOCK_UN); {Unlock Port}
fdClose(Fd); {Close Port}
end { if Fd > 0 }
else begin
writeLn('error, opening port ', port);
quit := true;
Is_error := -1;
end;
TheLine := ResStr;
GetLine := Is_Error;
end;{function GetLine}
(I'm not a very experienced programmer, so forgive me bad style, if there is ...). Thanks for hints ... RUDOLF
Rudolf Harney
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