X-Git-Url: https://ncurses.scripts.mit.edu/?a=blobdiff_plain;f=doc%2Fhtml%2Fman%2Fcurs_getcchar.3x.html;h=adee87eb87778cfc4e8a67777149076a1588e9a5;hb=349761f30e7fc0b4bf2718f7fc3da34e09ea6735;hp=34d4aae0e6dbd5f1b3aa72bb4fb8f6bf435b23d1;hpb=06078d3fa68db669ed37178c01873546b4b28745;p=ncurses.git diff --git a/doc/html/man/curs_getcchar.3x.html b/doc/html/man/curs_getcchar.3x.html index 34d4aae0..adee87eb 100644 --- a/doc/html/man/curs_getcchar.3x.html +++ b/doc/html/man/curs_getcchar.3x.html @@ -1,6 +1,7 @@
- +@@ -143,6 +144,53 @@ ERR. +
+ The CCHARW_MAX symbol is specific to ncurses. X/Open Curses does not + provide details for the layout of the cchar_t structure. It tells what + data are stored in it: + + o a spacing character (wchar_t, i.e., 32-bits). + + o non-spacing characters (again, wchar_t's). + + o attributes (at least 16 bits, inferred from the various ACS- and + WACS-flags). + + o color pair (at least 16 bits, inferred from the unsigned short + type). + + The non-spacing characters are optional, in the sense that zero or more + may be stored in a cchar_t. XOpen/Curses specifies a limit: + + Implementations may limit the number of non-spacing characters that + can be associated with a spacing character, provided any limit is + at least 5. + + The Unix implementations at the time follow that limit: + + o AIX 4 and OSF1 4 use the same declaration with an array of 5 non- + spacing characters z and a single spacing character c. + + o HP-UX 10 uses an opaque structure with 28 bytes, which is large + enough for the 6 wchar_t values. + + o Solaris xpg4 curses uses a single array of 6 wchar_t values. + + This implementation's cchar_t was defined in 1995 using 5 for the total + of spacing and non-spacing characters (CCHARW_MAX). That was probably + due to a misreading of the AIX 4 header files, because the X/Open + Curses document was not generally available at that time. Later (in + 2002), this detail was overlooked when beginning to implement the func- + tions using the structure. + + In practice, even four non-spacing characters may seem enough. X/Open + Curses documents possible uses for non-spacing characters, including + using them for ligatures between characters (a feature apparently not + supported by any curses implementation). Unicode does not limit the + (analogous) number of combining characters, so some applications may be + affected. + +
Functions: curs_attr(3x), curs_color(3x), curses(3x), wcwidth(3). @@ -163,6 +211,7 @@