On Thu, May 13, 2021 at 09:58:50PM +0200, Jaromír Doleček wrote: > Le jeu. 13 mai 2021 à 21:44, Joerg Sonnenberger <jo...@bec.de> a écrit : > > > No we don't, unless you are using PCC :D > > > > > > The block in <stdlib.h> only provides an alloca(3) prototype, and only > > > if the compiler already #defines alloca as __builtin_alloca. > > > > > > While this works for gcc in some -std modes (e.g. gnu++14), it does > > > not in others (c++14, c++11). > > > > Your analysis is wrong. We don't provide a prototype in standard modes > > as that violates the user request. The prototype is enough to trigger > > the builtin logic in GCC and Clang. > > Allright. > > Anyway, would it be wrong to add <alloca.h> which unconditionally > makes alloca() use the builtin, similar to what e.g. glibc (Linux) and > FreeBSD do, or is it fundamentally wrong doing so?
I don't see the point in it. The source is wrong to request strict C++14 compatibility and then use an extension. Just because Linux folks do that wrong doesn't mean we should cater to their bugs. Joerg
