The 09/23/2020 09:22, Szabolcs Nagy wrote: > The 09/21/2020 12:45, Martin Sebor via Gcc-patches wrote: > > On 9/21/20 12:20 PM, Vaseeharan Vinayagamoorthy wrote: > > > After this patch, I am seeing this -Warray-parameter error: > > > > > > In file included from ../include/pthread.h:1, > > > from ../sysdeps/nptl/thread_db.h:25, > > > from ../nptl/descr.h:32, > > > from ../sysdeps/aarch64/nptl/tls.h:44, > > > from ../include/errno.h:25, > > > from ../sysdeps/unix/sysv/linux/sysdep.h:23, > > > from ../sysdeps/unix/sysv/linux/generic/sysdep.h:22, > > > from ../sysdeps/unix/sysv/linux/aarch64/sysdep.h:24, > > > from <stdin>:1: > > > ../sysdeps/nptl/pthread.h:734:47: error: argument 1 of type ‘struct > > > __jmp_buf_tag *’ declared as a pointer [-Werror=array-parameter=] > > > 734 | extern int __sigsetjmp (struct __jmp_buf_tag *__env, int > > > __savemask) __THROWNL; > > > | ~~~~~~~~~~~~~~~~~~~~~~^~~~~ > > > In file included from ../include/setjmp.h:2, > > > from ../nptl/descr.h:24, > > > from ../sysdeps/aarch64/nptl/tls.h:44, > > > from ../include/errno.h:25, > > > from ../sysdeps/unix/sysv/linux/sysdep.h:23, > > > from ../sysdeps/unix/sysv/linux/generic/sysdep.h:22, > > > from ../sysdeps/unix/sysv/linux/aarch64/sysdep.h:24, > > > from <stdin>:1: > > > ../setjmp/setjmp.h:54:46: note: previously declared as an array ‘struct > > > __jmp_buf_tag[1]’ > > > 54 | extern int __sigsetjmp (struct __jmp_buf_tag __env[1], int > > > __savemask) __THROWNL; > > > | ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~ > > > cc1: all warnings being treated as errors > > > > The warning flags differences between the forms of array parameters > > in redeclarations of the same function, including pointers vs arrays > > as in this instance. It needs to be suppressed in glibc, either by > > making the function declarations consistent, or by #pragma diagnostic. > > (IIRC, the pointer declaration comes before struct __jmp_buf_tag has > > been defined so simply using the array form there doesn't work without > > defining the type first.) > > > > I would expect the warning to be suppressed when using the installed > > library thanks to -Wno-system-headers. > > why is this a warning? i'm not convinced it > should be in -Wall. > > this is a warning with false positives that > have no portable workaround and does not > really help catching bugs (at least i doubt > inconsistent array vs pointer declaration > is causing common problems). > > what gcc should warn about is if there is an > array style argument declaration and a caller > passes an array that's provably shorter than > that.
i take this back: such warning only makes sense when the static keyword is used in the array declarator. i really think this issue should be fixed in gcc and not in glibc: it's not true that the argument has array type, the standard requires the parameter type to be adjusted: A declaration of a parameter as "array of type" shall be adjusted to "qualified pointer to type" this warning will just confuse users and make them believe that the two declaration styles for pointer arguments are somehow different.
