[fpc-pascal] Using Serial in a TCP/RS232 gateway, how to set buffer sizes?

José Mejuto joshyfun at gmail.com
Fri Sep 8 16:23:04 CEST 2017

El 08/09/2017 a las 10:34, Bo Berglund escribió:

>    for i := 0 to l-1 do
>    begin
>      sLine := sLine + IntToHex(Buf[i],2);
>    end;
>    lbxLog.Items.Add(sTime + ' ' + sLine);
>    lbxLog.ItemIndex := lbxLog.Items.Count-1;


This is a big "NO, NO!" for quite large buffers, that code can take a 
lot of time for a 50K buffer, as it will render in the expected 50K 
inttohex conversions, but also (in worst and impossible case scenario) 
50K memory moves, 50K thread locks, 50K memory allocations and 50K 
memory frees.

Much better something like:

SetLength(sLine, Length(buf) * 2);
sLine := Prefix + ':' + sLine;

Please recheck params syntax for Bin2Hex, my memory is not as it used to 
be :-)

A large listbox is not also very good.


More information about the fpc-pascal mailing list