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<div class="moz-cite-prefix">On 04.04.2018 18:53, Jonas Maebe wrote:<br>
</div>
<blockquote type="cite"
cite="mid:93245b4c-8f2f-3399-3220-e942f1849269@freepascal.org">On
04/04/18 18:44, Ondrej Pokorny wrote:
<br>
<blockquote type="cite">I want to stress that the compiler emits a
warning on code that does not have (and also cannot have) an
error
<br>
</blockquote>
<br>
An error is wrong code behaviour. If you do not initialise a
variable with the correct value, then you can have an error.</blockquote>
<br>
No, no, no and again no. Do you try to convince me that I cannot
rely on well documented compiler behavior? Even Sven stated earlier
in this thread that the FPC docs are correct in case of managed
variables: "Managed types are an exception to this rule: Managed
types are always initialized: in general this means setting the
reference count to zero, or setting the pointer value of the type to
Nil." and "It should be stressed that initialized variables are
initialized when they come into scope"
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<br>
Again, the code<br>
procedure Test;<br>
var S: string; I: Integer;<br>
begin<br>
for I := 0 to 1 do<br>
S := S + '1';<br>
Writeln(S);<br>
end;<br>
<br>
does not have an error, cannot have an error and the behavior is
guaranteed and well documented => no warning should be here.<br>
<br>
+ Do you try to convince me that the code below can have an error
and should emit a warning as well because it does not initialize the
FS and FI fields?<br>
<br>
program Project1;<br>
type<br>
TMyObject = class<br>
private<br>
FS: string;<br>
FI: Integer;<br>
public<br>
property S: string read FS write FS;<br>
property I: Integer read FI write FI;<br>
end;<br>
<br>
begin<br>
with TMyObject.Create do<br>
begin<br>
Writeln(S);<br>
Writeln(I);<br>
Free;<br>
end;<br>
end.<br>
<br>
It's the same case - object fields are documented to be initialized.
You mean I should not rely on this feature and it is an error that I
did not initialize them with the correct values?<br>
<br>
<blockquote type="cite"
cite="mid:93245b4c-8f2f-3399-3220-e942f1849269@freepascal.org">This
correct value can be different from "empty string" or "nil".
</blockquote>
<br>
If I want to have a different value from "empty string" or "nil" I
know I have to initialize it by myself. I don't need a warning for
it.<br>
<br>
<blockquote type="cite"
cite="mid:93245b4c-8f2f-3399-3220-e942f1849269@freepascal.org">For
the same reason, we also warn about uninitialised global variables
(if this can be detected without interprocedural analysis, i.e.,
if they are only used in the main program code; but that is merely
due to a limitation of the analysis).</blockquote>
<br>
Uninitialised global variables are the same case: the compiler
should not emit a warning here because again, it is well documented
that they are implicitely initialized (at least in the Object Pascal
Language Guide from Borland from 2002 it is documented).<br>
<br>
Ondrej<br>
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