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).