The explain_setlinebuf_or_die function is used to call the
setlinebuf(3) system call. On failure an explanation will be
printed to stderr, obtained from the explain_setlinebuf(3)
function, and then the process terminates by calling
exit(EXIT_FAILURE).
The explain_setlinebuf_on_error function is used to call the
setlinebuf(3) system call. On failure an explanation will be
printed to stderr, obtained from the explain_setlinebuf(3)
function, but still returns to the caller.
fp
The fp, exactly as to be passed to the setlinebuf(3) system call.
RETURN VALUE
The explain_setlinebuf_or_die function only returns on success, see
setlinebuf(3) for more information. On failure, prints an
explanation and exits, it does not return.
The explain_setlinebuf_on_error function always returns the value
return by the wrapped setlinebuf(3) system call.
EXAMPLE
The explain_setlinebuf_or_die function is intended to be used in a
fashion similar to the following example: