HP-UX Reference (11i v1 05/09) - 2 System Calls (vol 5)

send(2) send(2)

has been shut down either by the remote peer or by this side of the connection.

Note that the default action for SIGPIPE, unless the process has established a

signal handler for this signal, is to terminate the process.

[EWOULDBLOCK] Nonblocking I/O is enabled using

ioctl() FIOSNBIO request and the

requested operation would block.

DEPENDENCIES

UDP messages are fragmented at the IP level into Maximum Transmission Unit (MTU) sized pieces; MTU

varies for different link types. These pieces, called IP fragments, can be transmitted, but IP does not

guarantee delivery. Sending large messages may cause too many fragments and overrun a receiver’s abil-

ity to receive them. If this happens the complete message cannot be reassembled. This affects the

apparent reliability and throughput of the network as viewed by the end user.

The default and maximum buffer sizes are protocol-speciﬁc. Refer to the appropriate entries in Sections 7F

and 7P for details. The buffer size can be set by calling

setsockopt() with SO_SNDBUF.

AF_CCITT

If the receiving process is on a Series 700/800 HP-UX system, and the connection has been set up to use the

D-bit, data sent with the D-bit set is acknowledged when the receiving process has read the data. Other-

wise, the acknowledgement is sent when the ﬁrmware receives it.

OBSOLESCENCE

Currently, the

socklen_t and size_t types are the same size. This is compatible with both the UNIX

95 and UNIX 98 proﬁles. However, in a future release, socklen_t might be a different size. In that

case, the size of the msghdr and cmsghdr structures and the relative position of their members will be

different, which might affect application behavior. Applications that use socklen_t now, where

appropriate, will avoid such migration problems. On the other hand, applications that need to be portable

to the UNIX 95 proﬁle should follow the X/Open speciﬁcation (see xopen_networking(7)).

FUTURE DIRECTION

Currently, the default behavior is the HP-UX BSD Sockets; however, it might be changed to X/Open

Sockets in a future release. At that time, any HP-UX BSD Sockets behavior that is incompatible with

X/Open Sockets might be obsoleted. Applications that conform to the X/Open speciﬁcation now will avoid

migration problems (see xopen_networking(7)).

AUTHOR

send(), sendmsg() , and sendto() were developed by HP and the University of California, Berkeley.