[fpc-pascal] Thread Safety of String

[md at rpzdesign.com]

I thought I had publicly declared what I wanted to do.

Here is the example code again for ease of reference:

Type
  Class TTest(TObject)
  public
    nflag : integer ;
    sflag : string[30]
  end;


Gui Thread

gtest := TTest.Create ;

Thread #1 - Constantly changing values

while true do
begin
 gtest.nflag := Random($FFFFFFFF) ;
 gtest.sflag := inttostr(gtest.nflag) ;
end;

Thread #2 - Constantly Comparing values

While true do
begin

  if gtest.nflag = 777888 then
  begin
    break ;
  end;

  //Test string matching instead of integer matching
  if gtest.sflag = '123456' then
  begin
    LaunchSpaceShuttle(gtest) ;
  end;

end;

Will this code be thread safe in terms of the gtest.sflag = '123456'
line never throw an exception because it is referring to stable memory
that is always less than 31 bytes.

Cheers,

marco



On 6/4/2014 3:27 PM, Mattias Gaertner wrote:
> On Wed, 04 Jun 2014 15:03:31 -0400
> "Saunders, Rich" <greymont at mykolab.com> wrote:
> 
>> [...]
>> Whether static variables are more or less thread safe is for you to 
>> decide since you know what you are doing with them. I don't think either 
>> short strings or Strings are inherently more or less thread safe. It 
>> depends on what you do with them.
> 
> No data is "thread safe". Only code can be thread safe.
> 
> Mattias
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