(doc?) locale-gen disagrees with locale(5)

[Hugo van der Sanden]

The LC_NUMERIC section of locale(5) includes:

       decimal_point
              followed by the string that will be used as the decimal delim-
              iter when formatting numeric quantities.

.. without constraint on what the string may include. However locale-gen appears to reject any attempt to define decimal_point to a string longer than one character, with the message:
  LC_NUMERIC: value for field `decimal_point' must be a single character
  [error] LC_NUMERIC: field `decimal_point' not defined

If that constraint is intended, I think locale(5) should specify it. (There may be a similar issue for thousands_sep, I didn't test that.)

Found on bionic with locales-2.27-3ubuntu1.2, I did not check other releases.

Motivation: I wanted to define a longer decimal_point so as to test the robustness of an application's number formatting.

[Gunnar Hjalmarsson (gunnarhj)]

Thanks for your report. Looks like there is room for clarification of that man page.

I would suggest that you report it upstream:

https://sourceware.org/bugzilla/enter_bug.cgi?product=glibc;component=locale

But don't refer to locale-gen() when doing so, but rather localedef(). Also, if you file an upstream bug, please post the URL to it here.

[Hugo van der Sanden (hugovds)]

In the section for LC_NUMERIC, locale(5) says:

  decimal_point
    followed by the string that will be used as the decimal delim-
    iter when formatting numeric quantities.

.. without constraint on what the string may include. It appears this is actually constrained by processors to be a single character, as at https://code.woboq.org/userspace/glibc/locale/programs/ld-numeric.c.html#229

It is not clear if that is part of the spec: if so, I think this should be made explicit in the man page; if not, it is probably still worth noting that some applications (such as localedef) require it.

I have not checked, but it seems likely that thousands_sep has the same constraint, and would need similar treatment.

Initially reported for Ubuntu at https://bugs.launchpad.net/ubuntu/+source/glibc/+bug/1898902, they recommended I re-post upstream.

[Hugo van der Sanden (hugovds)]

Thanks, reported upstream at https://sourceware.org/bugzilla/show_bug.cgi?id=26715

[Florian Weimer (fweimer)]

The manual pages are maintained by the Linux man-pages project. I submitted a patch: https://<email address hidden>/T/

[Florian Weimer (fweimer)]

Please note that the manual pages come from the Linux man-pages project, not glibc. I posted a patch: https://<email address hidden>/T/