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Re: alias question


On 02/18/2011 10:40 AM, Segher Boessenkool wrote:
If I have a char array, and it's always written by the char array, can
it
be always reliably read by any combination of short/int/long pointers?

As I understand, the compiler will see byte writes for all types, so
readind shoulg be fine without violating any strict alias rules.  Just
can't write the array by any other type than char[] access.  Right?

No. You can access anything only as its declared type or character type; an array of char thus can be accessed as char only.

Not quite: if you write an int to an array of char, you can read it back again. What matters is the effective type.

Of course, but the effective type is equal to the declared type (if there is any) of the object, so that write as int is undefined behaviour already!

No: character types are special. See Section 6.5 re arrays of character type and effective types.

Andrew.


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