low-level knowledge of your friendly neighbourhood C compiler

Alan J Rosenthal flaps at dgp.toronto.edu
Thu May 3 05:08:37 AEST 1990


henley at motcid.UUCP (Aaron Henley) writes:
>I think people should and in many cases must be aware of how their compiler
>allocates memory for structures, what happens when you typecast a word from a
>memory location starting at a point that isn't word aligned, etc...  These and
>many other usages of C are ambiguously defined.

This is completely wrong.  These things are UNDEFINED, not at all ambiguous.
The following two statements are both unambiguously false:
	a) dereferencing a misaligned pointer in C dumps core; and
	b) dereferencing a misaligned pointer in C doesn't dump core.
That's what undefined means.  It doesn't mean that one of them is true.

ajr



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