Is Unix stdio slow?

[Edward Wang]

In article <13853 at mimsy.UUCP> chris at mimsy.UUCP (Chris Torek) writes:
>. . . _doprnt
>assumes that a negative _cnt field is an error, and clobbers the
>count.  Every once in a while, this results in putc scribbling all over
>memory.  Fortunately, instances of this bug are rare (it requires
>mixing calls to printf and calls to putc in a particular way).  This is
>fixed in 4.3BSD-tahoe, which no longer has _doprnt in Vax assembly.

Well I don't know about this, but the negative _cnt field
is as old as line buffering, before the fast putc.  The old
putc depended on the negative _cnt to invoked _flsbuf
for line buffered streams (the --fp->_cnt >= 0 test always
fails so _flsbuf is always called).

But enough on this already.