On Thu, May 17, 2018 at 6:04 PM, Kaz Kylheku (Coreutils) < 962-396-1...@kylheku.com> wrote:
What are the requirements underpinning "wc -m", and how do these > iswprint and iswspace functions fit into it? > … > Nowhere does POSIX say that the display width of a character > has to be obtained in "wc" and I don't see that in the GNU documentation > either. The GNU requirement for calling wcwidth (if -L is specified) is the claim in coreutils.texi (added in f325d180c, in 2008) that "[t]he line lengths here are measured in screen columns, according to the current locale and assuming tab positions in every 8th column." It doesn't know the screen columns without calling wcwidth to measure the characters. The POSIX requirement for calling iswspace (if -w is specified) is the POSIX definition of a word as "non-zero-length string of characters delimited by white space." It doesn't know whether a multibyte character counts as white space without calling iswspace. Neither of them really ought to depend on whether -m is specified, which (at least in POSIX) only has to do with whether wc is counting characters instead of bytes. Eric
