On Wed, 11 Jun 2014, David Rientjes wrote: > > > ieee754dp has bitfield member in struct without name. And this > > > cause compilation error. This patch removes struct in ieee754dp > > > declaration. So compilation error is fixed. > > > Signed-off-by: Eunbong Song <eunb.song@xxxxxxxxxxx> > > > > What gcc version are you using? > > > > make arch/mips/math-emu/ieee754.o for mips defconfig triggers the > following on linux-next 30 times: > > arch/mips/math-emu/ieee754.c:45:2: error: unknown field 'sign' specified in initializer > arch/mips/math-emu/ieee754.c:45:2: warning: missing braces around initializer > arch/mips/math-emu/ieee754.c:45:2: warning: (near initialization for '__ieee754dp_spcvals[0].<anonymous>') > arch/mips/math-emu/ieee754.c:45:2: error: unknown field 'bexp' specified in initializer > arch/mips/math-emu/ieee754.c:45:2: warning: excess elements in union initializer > arch/mips/math-emu/ieee754.c:45:2: warning: (near initialization for '__ieee754dp_spcvals[0]') > arch/mips/math-emu/ieee754.c:45:2: error: unknown field 'mant' specified in initializer > arch/mips/math-emu/ieee754.c:45:2: warning: excess elements in union initializer > arch/mips/math-emu/ieee754.c:45:2: warning: (near initialization for '__ieee754dp_spcvals[0]') > > I'm using gcc 4.5.1 for mips. The patch makes all members part of the > union so it's probably not what you want to fix it, though. There's more recent breakage like this, e.g.: mm/page_io.c: In function '__swap_writepage': mm/page_io.c:277: error: unknown field 'bvec' specified in initializer mm/page_io.c:278: warning: excess elements in struct initializer mm/page_io.c:278: warning: (near initialization for 'from') introduced with "bio_vec-backed iov_iter" (GCC 4.1.2 here). We still in principle support GCC versions back to 3.2: $ grep 'Gnu C' Documentation/Changes o Gnu C 3.2 # gcc --version $ so either this breakage has to be cleaned up or the requirement for the minimum GCC version revisited. This is a semi-standard language extension BTW, citing from the GCC manual: -------------------------------------------------------------------------- 6 Extensions to the C Language Family ************************************* GNU C provides several language features not found in ISO standard C. (The `-pedantic' option directs GCC to print a warning message if any of these features is used.) To test for the availability of these features in conditional compilation, check for a predefined macro `__GNUC__', which is always defined under GCC. 6.59 Unnamed struct/union fields within structs/unions ====================================================== As permitted by ISO C11 and for compatibility with other compilers, GCC allows you to define a structure or union that contains, as fields, structures and unions without names. -------------------------------------------------------------------------- -- note the term "permitted" rather than "required". We do make use of a few GCC language extensions, most notably inline assembly, however in this case we merely save a couple of characters here and there and this is IMO not worth breaking people's development environments. Maciej
