Re: printf %b

[Alejandro Colomar <colomar.6.4.3@gmail.com>]

On 4/26/20 4:29 AM, Alejandro Colomar wrote:
 > Hmmm.  Good point.  Maybe, given that binary doesn't have letters such
 > as hex does, we don't need both ``%b`` and ``%B``.  We could have just
 > ``%B`` (if it isn't already taken by some other thing) and use it for
 > binary.

I have written the patch to add ``%B`` (not ``%b``) for binary.  I added
a few tests to ``stdio-common/tst-printf.c``, which work fine.  I also
compiled the extensive test that I had for my library, with the new
glibc, and it worked also fine.

Issues:

  - Not yet implemented:  Separator for nibbles. (If I implement this, I
    would like to also implement it for hex bytes).
  - GCC 9 doesn't know of this specifier, so in the tests I had to
    disable that diagnostic.  When GCC accepts it, those pragmas should
    be removed.
  - ``stdio-common/tst-printfsz.c`` registers ``%B`` for something else
    (it uses ``register_printf_function()``, so it overwrites the
    specifier, and shouldn't cause any problems at all).

TODO (I will do them ASAP (when I know howto, actually)):

  - Documentation (both glibc and man 3 printf).
  - patch GCC to accept the new specifier.

I had some problems following the `contribution checklist`_:

_`contribution checklist`: 
https://sourceware.org/glibc/wiki/Contribution%20checklist

  - ``find . -name ChangeLog`` shows nothing to me:

::

	$ find . -name ChangeLog
	$ find . |grep ChangeLog
	./ChangeLog.old
	./ChangeLog.old/ChangeLog.ports-m68k
	./ChangeLog.old/ChangeLog.9
	./ChangeLog.old/ChangeLog.4
	./ChangeLog.old/ChangeLog.13
	./ChangeLog.old/ChangeLog.ports-tile
	./ChangeLog.old/ChangeLog.5
	./ChangeLog.old/ChangeLog.ports-arm
	./ChangeLog.old/ChangeLog.16
	./ChangeLog.old/ChangeLog.localedata
	./ChangeLog.old/ChangeLog.8
	./ChangeLog.old/ChangeLog.ports-microblaze
	./ChangeLog.old/ChangeLog.ports-aarch64
	./ChangeLog.old/ChangeLog.ports-am33
	./ChangeLog.old/ChangeLog.ports-mips
	./ChangeLog.old/ChangeLog.ports-aix
	./ChangeLog.old/ChangeLog.nptl_db
	./ChangeLog.old/ChangeLog.ports-hppa
	./ChangeLog.old/ChangeLog.6
	./ChangeLog.old/ChangeLog.14
	./ChangeLog.old/ChangeLog.1
	./ChangeLog.old/ChangeLog.ports-powerpc
	./ChangeLog.old/ChangeLog.nptl
	./ChangeLog.old/ChangeLog.7
	./ChangeLog.old/ChangeLog.19
	./ChangeLog.old/ChangeLog.15
	./ChangeLog.old/ChangeLog.2
	./ChangeLog.old/ChangeLog.ports
	./ChangeLog.old/ChangeLog.18
	./ChangeLog.old/ChangeLog.libidn
	./ChangeLog.old/ChangeLog.12
	./ChangeLog.old/ChangeLog.11
	./ChangeLog.old/ChangeLog.ports-ia64
	./ChangeLog.old/ChangeLog.20
	./ChangeLog.old/ChangeLog.ports-cris
	./ChangeLog.old/ChangeLog.ports-linux-generic
	./ChangeLog.old/ChangeLog.ports-alpha
	./ChangeLog.old/ChangeLog.10
	./ChangeLog.old/ChangeLog.17
	./ChangeLog.old/ChangeLog.3

  - I couldn't create an account on http://patchwork.sourceware.org/
    because that link is broken (500 Internal server error).

Regards,
		Alex.