On Thu, 7 Jan 2010, Peter Stuge wrote:
>> In my reading, the man page is quite clear that returning 0 is
>> indeed not an error.
>
> Only implicitly.
Let me quote what the libssh2_channel_read_ex man page says:
Note that a return value of zero (0) can in fact be a legitimate value
and only signals that no payload data was read. It is not an error.
That is about as explicit you can get in my book.
> But even if it was more clear, the behavior is quite counter-intuitive.
> (Compare read() or even SSL_read() where 0 is a special case.)
My man page for read() says the following on RETURN VALUE:
Upon successful completion, read() and pread() shall return a non-
negative integer indicating the number of bytes actually read. Other‐
wise, the functions shall return -1 and set errno to indicate the
error.
... there's no special case for 0 there.
But yes, SSL_read() special cases 0 but that (again) only shows the need for
a non-blocking mode...
You do surprise me though, as I was under the impression you wanted 0 to be a
non-error case. If 0 is not a legitimate return code, what is the function to
returned when no "payload data" has read and no error occurred?
-- / daniel.haxx.se
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Received on 2010-01-07