On 2019-12-17 16:27:28 +0100, Manfred wrote: > On 12/17/2019 2:22 PM, Segher Boessenkool wrote: > > Is there *any* portable way to print function pointers? Other than > > accessing it as bytes :-) > > n1570 section 6.3.2.3 p6 says "Any pointer type may be converted to an > integer type. Except as previously specified, the result is > implementation-defined. ..." > > It says implementation-defined, not undefined, IMHO, the difference matters mainly for the implementer: in short, he must not ignore the issue. But an implementation-defined behavior (or result) can be almost as useless as undefined behavior. > so AFAIU it is legal, although you can't make assumptions on the > actual value of the result. > > However, 7.20.1.4 specifies intptr_t and uintptr_t for pointers to void > only, and 6.3.2.3 p1 specifies the conversion to/from pointers to void and > pointers to "any object type" which does not include functions, AFAIU. > So, unless I am missing something, there seems indeed to be a broken link in > the chain from pointer to function to (u)intptr_t. > But then what's the purpose of 6.3.2.3 p6 ? I would have actually preferred undefined behavior with a diagnostic. I'm wondering why a programmer would want to convert a pointer to an integer (except as a workaround to bizarre limitations, which would better be solved directly by the standard). -- Vincent Lefèvre <vincent@xxxxxxxxxx> - Web: <https://www.vinc17.net/> 100% accessible validated (X)HTML - Blog: <https://www.vinc17.net/blog/> Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)
