On 02/03/13 5:45, Flávio Etrusco wrote:
On Fri, Mar 1, 2013 at 11:49 PM, Xiangrong Fang <[email protected]> wrote:
Hi there,
If my class constructor looks like this:
constructor TMyClass.Create(fn: string);
begin
sl := TStringList.Create;
try
fs := TFileStream.Create(fn, fmOpenRead);
except
self.Destroy;
end;
end;
I create the objec like: MyInstance :=
TMyClass.Create('AnNonExistentFile'); An exception occured, I can ensure
that:
1. there is no memory leak.
I assume FPC behaves like Delphi, so there's no leak.
Actually, you don't even need to explicitly call Destroy; when an
exception occurs in a constructor the destructor is called
automatically.
2. the MyInstance variable is assigned nil?
No, it's not initialized.
But you can write:
constructor TMyClass.Create(fn: string);
var fs: TFileStream;
begin
sl := TStringList.Create;
try
fs := TFileStream.Create(fn, fmOpenRead);
except
self:= nil;
end;
end;
which gives no memory leak, (provided your destructor frees the
stringlist sl) and also ensures MyInstance is assigned a nil value.
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