On Tue, Jan 07, 2014 at 10:48:53AM +0100, Geert Uytterhoeven wrote: > On Tue, Jan 7, 2014 at 6:55 AM, Sam Ravnborg <sam@xxxxxxxxxxxx> wrote: > > On Mon, Jan 06, 2014 at 12:47:07PM -0800, Josh Triplett wrote: > >> [CCing build-system folks and others likely to know about potential > >> issues.] > >> > >> Does anyone have any objection to the use of "#pragma once" instead of > >> the usual #ifndef-#define-...-#endif include guard? GCC, LLVM/clang, > >> and the latest Sparse all support either method just fine. (I added > >> support to Sparse myself.) Both have equivalent performance. "#pragma > >> once" is simpler, and avoids the possibility of a typo in the defined > >> guard symbol. > > For kernel headers no concern. > > Just being cautious: > > Do we know the minimum gcc version that supports #pragma once? >From checking the manuals, it goes back to at least 2.95. Searching suggests that versions before 3.4 have a few bugs in "#pragma once" support, but that those bugs only apply to using #pragma once in combination with precompiled headers, which doesn't apply to the kernel. - Josh Triplett -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
