On Tue, 1 Sep 2020, Bo Berglund via fpc-pascal wrote:
On Tue, 01 Sep 2020 10:22:08 +0200, Bo Berglund via fpc-pascal
<fpc-pascal@lists.freepascal.org> wrote:
Maybe I could tie the timeout to the actual baud used? Slower speeds
use longer timeout etc? Timeout could be set to the time it takes to
transfer the number of bytes to read?
And both arguments could be made properties of the class such that the
user can tweak performance a bit?
I tried to do this:
TComPortReadThread=class(TThread)
private
FBuffer: TBytes;
FPacketSize: integer; default 10;
FReadTimeout: integer; default 10;
public
MustDie: boolean;
Owner: TFpSerialPort;
property ReadPacketSize: integer read FPacketSize write
FPacketSize; //How many bytes to read in each operation
property ReadTimeout: integer read FReadTimeout write
FReadTimeout; //Max time to wait for data in thread
protected
procedure CallEvent;
procedure Execute; override;
published
property Terminated;
end;
But I cannot set the default value of the two new fields FPacketSize
and FReadTimeout, I get an error in the above code (and variations of
the same).
Is there no way to declare a property to have a default non-zero
value?
You must set it on the property:
Property property ReadPacketSize: integer read FPacketSize write FPacketSize
default 10;
Note that this does not actually set the property to the indicated value. It
is only a hint for the streaming system:
You must still set the default value in the constructor.
Note that the thread itself has no idea what is the baudrate in use so
it cannot calculate the proper value at the start of Execute...
And there is no Create method either that I can use.
The constructor can always be overridden.
Michael.
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