Re: [9fans] ... in the Kingdom of Sources

["Douglas A. Gwyn" <DAGwyn@null.net>]

rob pike, esq. wrote:
> there are two important differences.  first is that (old) ANSI C
> did not provide any formatted i/o for wchar_t, rendering them
> essentially useless.

The target clientele at the time insisted that they did not want
us to specify more than the minimum necessary support, and that
they would happily invoke the multibyte<->wide conversions when
necessary.  I remember Plauger relaying that promise.  Not
surprisingly, as soon as they got the capability they started
pushing for the missing functions, which became part of a
normative amendment to the C standard by 1995 (along with mode
on the stream to control whether automatic conversion is or is
not applied).

> the way plan 9 handles encoding errors with runetochar
> and chartorune, by introducing the 'error rune' 0x80, is vastly
> more convenient and effective than the error return values set
> by mbtowchar stuff.

Since an encoding error should "never" occur, we thought it
better to stop scanning rather that plow ahead and convert some
unknown amount of garbage once synchronization has been lost.
It was also not evident that there would always be a "spare"
wide-character code available for in-band signaling.

I think the main difference driving the designs is that the
Standard C version has to accommodate a huge variety of
multibyte and internal encoding systems, whereas Plan 9 could
just pick one.

Anyway, the C wide-character facilities are quite similar to
the legacy char-based ones, so Boyd shouldn't be finding them
"confusing".