todo

早期freebsd实现

	KNOWN PROBLEMS AND PLANNED CHANGES

* Finish missing stdio functions

mktemp
getw, putw
fgetline? fpurge? snprintf? (sprintf w/limit) vsnprintf? (BSD)

* Optimize

String writes (printf, fwrite, sputn, fputs,puts,  ...)

* filebuf

Test and study for unusual uses: unbuffered files, putback,
seeking, read+write files, ...

* editbuf

Clear up memory use conventions.  Perhaps reference count marks.

* parsebuf

Clean up: Get rid of unused fields; nail down first-line conventions.
Re-write to use backup capability.

* iostream:

Define eofbit and badfile to use stream's eof and err flags?
Use width for input, precision.
Formatting of floats and doubles.
User-defined ios flags.

Manipulators (use templates)

Assignment of standard streams (cin, cout, cerr)

* streambuf sub-classes for talking to ptys and/or sockets

* Make sure that errors  (e.g. write errors) get propagated
(set _S_ERR_SEEN, set ios::badbit).

* Documentation!!!