learning c

[Guy Harris]

>I don't know what the ANSI standard says, but for now it probably
>doesn't matter.

It says that the behavior is undefined if you do an "fflush" on an
read-only stream or a read/write stream in which the most recent
operation was not an input operation.  Translation: "fflush" doesn't
flush input, so the ANSI standard says nothing new - it says "it flushes
output, we make no claims about input", which reflects current practice
(S5R3's "fflush" appears to flush input, although it's not documented -
which is kind of obnoxious; either it's a useful feature, in which case
it should be documented and supported, or it's a useless one, in which
case it shouldn't have been put in; 4.3-tahoe's doesn't; Turbo C's is
documented as doing so and presumably does; etc..)