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From: Adriaan van Os
Subject: cast increases required alignment of
Date: 10 Sep 2004, 17:36:29

Frank Heckenbach wrote:

>> 1. Compiling with gpc produces two warnings as indicated in the
>> comment. The compiler warns if the "casting" pointer type (outside the
>> parenthesis) points to a larger type than the "casted" pointer type
>> (inside the parenthesis).
>
> Not really. As the message says, it warns that the alignment, not
> size, of the target type is larger.
>
>> Gale Paper brought to my attention that the
>> same holds on the left side of an assignment and I am inclined to
>> regard this as a bug - the compiler should check here for a smaller
>> type, rather than a larger type.
>
> While casting to a smaller type can be dangerous in some cases, so
> can any pointer conversion, so I'm not convinced that this case
> deserves particular attention.

Well, OK, the warning is about alignments not about sizes. Thanks for 
pointing that out.

Still I am not convinced that

	theIntPtr:= IntPtr( theBytePtr);       {testcast.pas:11: warning: cast 
increases required alignment of target type}

should produce a warning and left-side equivalent shouldn't

	BytePtr( theIntPtr)	:= theBytePtr;

Both statements have the same effect. Actually, the target is in both 
cases a variable of type Integer. So, at the left side of an 
assignment, the target is the innermost type of the cast, not the 
outermost.

The same remarks apply for

	theBytePtr:= BytePtr( theIntPtr);
	IntPtr( theBytePtr):= theIntPtr;      {testcast.pas:14: warning: cast 
increases required alignment of target type}

but then the other way round.

Regards,

Adriaan van Os

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