[PATCH 2/2] ctype: use less short names in public header

Richard Earnshaw Richard.Earnshaw@foss.arm.com
Wed Nov 24 10:58:57 GMT 2021

On 24/11/2021 04:15, Mike Frysinger wrote:
> On 23 Nov 2021 15:09, Richard Earnshaw wrote:
>> This is wrong and breaks all old versions of C++.
> this is a bit vague.  it would help if you provided details as to what broke.
> i doubt this broke all old versions of C++ everywhere.

My apologies, I did mean to say GNU C++.
> i'm guessing you're referring to the GNU C++ (libstdc++) library specifically
> and its hardcoding of newlib's internal ctype define names.
> https://gcc.gnu.org/git/?p=gcc.git;a=blob;f=libstdc%2B%2B-v3/config/os/newlib/ctype_base.h;hb=releases/gcc-11.2.0
> if you're talking about something else, please state so clearly.
>> The GNU sim code should not be using reserved names (those starting _) 
>> in normal source code.  Such names are reserved to the implementation.
> that's not really a good reason to go pooping all over the namespace.
It's not 'pooping' on the namespace.  Identifiers starting with _ are
all reserved, one way or another; some for the compiler, some for the
library implementation and some for future changes to the standard.
Applications have no business defining such names.

> we can maintain backwards compat here for C++ code fairly easily:
> --- a/newlib/libc/include/ctype.h
> +++ b/newlib/libc/include/ctype.h
> @@ -71,6 +71,16 @@ enum
>  /* For C++ backward-compatibility only.  */
>  extern	__IMPORT const char	_ctype_[];
> +#ifdef __cplusplus
> +# define _U _ISupper
> +# define _L _ISlower
> +# define _N _ISdigit
> +# define _S _ISspace
> +# define _P _ISpunct
> +# define _C _IScntrl
> +# define _X _ISxdigit
> +# define _B _ISblank
> +#endif

>  #ifdef __HAVE_LOCALE_INFO__
>  const char *__locale_ctype_ptr (void);
> considering the numerical value is part of the ABI, not the name, libstdc++
> could have inlined the constant values instead.  i wonder how long of a version
> skew is reasonable if we wanted to transition it to the new names to match what
> glibc uses.

I think you'll find that the BSD libraries have been using _[ULNSPCXB]
since pretty much forever.  Why do we need to be compatible with glibc?


> -mike

More information about the Newlib mailing list