On Tue, 16 Jul 2002, Brad Nicholes wrote: > The problem with the MOD_CGI case is that it *doesn't* call > pipe_bucket_read() with APR_BLOCK_READ. In fact it calls it with > APR_NONBLOCK_READ which is what prompted the modification in the first > place. If your analysis as to the definitions of APR_BLOCK_READ vs > APR_NONBLOCK_READ is correct, then let me dig a little deeper in the > code to figure out exactly why MOD_CGI is ultimately passing an > APR_NONBLOCK_READ (unless somebody else already knows). What I do know > is that if pipe_socket_read() is allowed to return with an EWOULDBLOCK > error code, I end up with a browser response of "Premature end of > script..." when in fact the data is there, just not at the right time.
Justin's definition is correct as far as I'm aware. At the risk of stating the obvious: EWOULDBLOCK can only be returned in APR_NONBLOCK_READ mode. Any caller that does a nonblocking read *must* check for EWOULDBLOCK and loop or otherwise handle it. (A tight loop doesn't make any sense, of course... if that's all you're going to do, use APR_BLOCK_READ. APR_NONBLOCK_READ is only any good if you have other stuff to do while waiting on more input.) --Cliff
