Am 28.02.2012 08:40, schrieb Martin Schreiber:
Am 28.02.2012 09:23, schrieb Sven Barth:
For strings SetLength also fills the string with zeros as the following
example shows:
=== example begin ===
program setlengthtest;
var
barr: array of Byte;
b: Byte;
s: AnsiString;
c: Char;
begin
SetLength(barr, 20);
for b in barr do
Write(b, ' ');
Writeln;
SetLength(s, 20);
for c in s do
Write(Ord(c), ' ');
Writeln;
end.
=== example end ===
=== output begin ===
PS P:\tests\oneshots> .\setlengthtest.exe
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
=== output end ===
So SetLength is the operation to use in each case.
This is probably because in your testcase the memory is still clean, try
with -gh. Additionally this behavior would not be Delphi compatible:
"
When you use SetLength, existing characters in the string are preserved,
but the contents of any newly allocated space is undefined.
"
http://docwiki.embarcadero.com/RADStudio/en/Declaring_and_Initializing_Strings
You are right, I checked the code of SetLength for arrays and strings
and only arrays use FillChar. Nevertheless there is no other operation
you can use for arrays.
Regards,
Sven
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