On 25 January 2018 at 12:29, Jonathan Wakely wrote: > On 25 January 2018 at 12:27, Georg-Johann Lay wrote: >> On 22.01.2018 16:20, Jonathan Wakely wrote: >>> >>> On 21 January 2018 at 12:08, Georg-Johann Lay wrote: >>>> >>>> Jay K schrieb: >>>>> >>>>> >>>>> extern const int foo = 123; >>>>> >>>>> Why does this warn? >>>>> This is a valid portable form, with the same meaning >>>>> across all compilers, and, importantly, portably >>>>> to C and C++. >>>> >>>> >>>> I also wondered about this. >>>> >>>> In C99 ยง6.9.2 "External object definitions" there's actually >>>> the following example in clause 4: >>>> >>>> extern int i3 = 3; // definition, external linkage >>> >>> >>> That's a different case. There's no advantage to the 'extern' here, >>> because the code means the same thing in C and C++ without the >>> 'extern', so just leave it out. >> >> >> I'd rather like to know why GCC is throwing a warning here. >> >> It's clear how to hack the C source, but that's a different point. >> >> It's just the case that I don't see any problem with that construct, >> and it was worth an explicit example in the standard. Or is it >> common practice to warn constructs that are "no advantage"? > > Read https://gcc.gnu.org/bugzilla/show_bug.cgi?id=45977 (as already > stated earlier in the thread).
Also, examples in the standard exist to show what is technically valid, not what is good coding style.
