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From: TAYBENGH@NUSDISCS.BITNET (THE AGEIS)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: Blocking /non blocking
Message-ID: <A8BE454AE0DF801442@nusdiscs.bitnet>
Date: 11 Mar 91 08:51:49 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 15
X-Unparsable-Date: Mon, 11 Mar 91 15:53 SST

In-Reply-To:  your letter rec'd 11-MAR-1991 15:06:15.40


All the socket system calls (send, sendto, recv & recvfr ...) are blocking
calls. Blocking send means the send will be blocked if the send buffer is not
big enough (currently) to hold the data. If u choose to un-block the calls,
the system call returns whatever bytes u can put into the send buffer. For
the datagram calls, it the send data is larger than maximum set (can be
changed using setsockopt()), then the system will only send the maximum
allowed and return to u about the bytes send. Bon-blocking recv means
if there is no data present, the calls will just return -1 with errno
set EWOULDBLOCK.
Hope this helps.

- Beng Hang (email: taybengh@nusdiscs)