On Fri, Jun 16, 2023 at 5:43 AM Barry Revzin via Core <[email protected]> wrote:
> While I'm not sure it's a great idea to #define _, I think we should > generally err on the side of providing macros for features than not - since > we've missed a few over the years in ways that have mattered. > > Looks like the latest revision of the paper has one already. > > Thanks! > I would like to bikeshed the name, it should be __cpp__ Barry > > On Thu, Jun 15, 2023 at 12:33 AM Corentin via Core <[email protected]> > wrote: > >> + SG10 >> This pattern is principally used for global variables, for which >> placeholders are not allowed, so I doubt this would be useful. >> That being said, I defer to SG10 call, I'm happy to add one if >> people think it would have use cases. >> >> Thanks! >> >> >> >> >> >> >> >> On Wed, Jun 14, 2023 at 10:33 PM Christof Meerwald <[email protected]> >> wrote: >> >>> Not sure how widespread these workarounds are, but there are >>> stackoverflow questions related to this: >>> >>> >>> https://stackoverflow.com/questions/10379691/creating-macro-using-line-for-different-variable-names >>> >>> https://stackoverflow.com/questions/1082192/how-to-generate-random-variable-names-in-c-using-macros >>> https://stackoverflow.com/questions/461062/c-anonymous-variables >>> >>> (and I think I have seen real-world code using these workarounds) >>> >>> So I think the use case for a feature-test macro would be something >>> like this: >>> >>> #ifndef __unnamed_placeholder >>> #define CONCAT2(a, b) a ## b >>> #define CONCAT(a, b) CONCAT2(a, b) >>> #ifdef __COUNTER__ >>> #define _ CONCAT(placeholder, __COUNTER__) >>> #else >>> #define _ CONCAT(placeholder, __LINE__) >>> #endif >>> #endif >>> >>> void f() >>> { >>> int _ = 1; >>> int _ = 2; >>> } >>> >>> >>> Christof >>> >>> -- >>> >>> https://cmeerw.org sip:cmeerw at cmeerw.org >>> mailto:cmeerw at cmeerw.org xmpp:cmeerw at cmeerw.org >>> >> _______________________________________________ >> Core mailing list >> [email protected] >> Subscription: https://lists.isocpp.org/mailman/listinfo.cgi/core >> Link to this post: http://lists.isocpp.org/core/2023/06/14395.php >> > _______________________________________________ > Core mailing list > [email protected] > Subscription: https://lists.isocpp.org/mailman/listinfo.cgi/core > Link to this post: http://lists.isocpp.org/core/2023/06/14397.php >
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