On 4/29/20 12:29 PM, Marc Nieper-Wißkirchen wrote:
> It would be great if the flexmember exported another macro, say
> XFLEXSIZEOF, which returned SIZE_MAX in case of arithmetic overflow.
Something like this?
/* Like FLEXSIZEOF, except yield SIZE_MAX on arithmetic overflow,
and N might be evaluated more than once. */
#define XFLEXSIZEOF_XSIZE(type, member, n) \
(((n) <= FLEXSIZEOF (type, member, n) \
&& FLEXSIZEOF (type, member, n) <= (size_t) -1) \
? (size_t) FLEXSIZEOF (type, member, n) : (size_t) -1)
A couple of problems with this approach:
* It evaluates N more than once.
* If the FLEXSIZEOF calls appears in a ptrdiff_t context it might not
return the right value. ptrdiff_t is also a popular way
to compute sizes.
But perhaps it's good enough.
