When tm structure is described in the ctime(3), it's supposed to be rendered as C code, with asterisks for char pointer (tm_zone) and comments (/* ... */). However, they may not be displayed correctly, depending if the user's font has the glyph for U+2217 (∗) ASTERISK OPERATOR (hex e2 88 97). For example, Luxi, DroidSans, DejaVuSans monospaced fonts have it, but e.g. Consolas does not (it renders nothing). With traditional "fixed" font, dotted square is drawn. On the FreeBSD virtual console with default settings, a square is drawn.
Would it be possible to use the simple ASCII asterisks instead, like everywhere else in that page? As I read in the commit history of this file, although it is under contrib, it has diverged sufficiently from upstream (including a full whitespace commit and large portions rewritten), so perhaps we can also replace these Unicode asterisks with ASCII ones so it renders correctly everywhere.
It also seems odd to me that mdoc is rendering '\(**' as unicode asterisks at all. (Well, I am surprised Unicode has a 2nd asterisk character as well; it seems useless.)
Special characters are used to encode special glyphs ...
Sequences begin with the escape character ‘\’ followed by
either an open-parenthesis ‘(’ for two-character sequences...
\(em Two-letter em dash escape.
\(cc Special Characters with two-letter names, see mandoc_char(7).
I guess that explains \(**.
Input Rendered Description
\(** ∗ asterisk
Ok, so \(** is just wrong here. C comments are not some mathematical formula.
A commit references this bug:
Date: Fri May 22 15:30:14 UTC 2020
New revision: 361385
ctime.3: Use ASCII asterisks for C, not special unicode math glyphs
Reported by: danfe