HP-UX Reference (11i v1 00/12) - 2 System Calls (vol 5)

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STANDARD Printed by: Nora Chuang [nchuang] STANDARD

/build/1111/BRICK/man2/!!!intro.2

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___ ___

recv(2) recv(2)

getsockopt(2).)

[EBADF] The argument s is an invalid descriptor.

[ECONNRESET] A connection was forcibly closed by a peer.

[EFAULT] An invalid pointer was speciﬁed in the buf , from , or fromlen parameter, or in

the msghdr structure.

[EINTR] The receive was interrupted by delivery of a signal before any data was available

for the receive.

[EINVAL] The len parameter or a length in the msghdr structure is invalid; or no data is

availableon receive of out of band data.

[EMFILE] The number of ﬁle descriptors available to the calling process has been exceeded.

[EMSGSIZE] A length in the msghdr structure is invalid.

[ENOBUFS] Insufﬁcient resources were availablein the system to perform the operation.

[ENOSR] Buffers could not be allocated for the message that was to be created due to

insufﬁcient STREAMS memory resources.

[ENOTCONN] Receive on a SOCK_STREAM socket that is not yet connected.

[ENOTSOCK] The argument s is a valid ﬁle descriptor, but it is not a socket.

[EOPNOTSUPP] The MSG_OOB ﬂag was set for a UDP SOCK_DGRAM message-based socket, or

MSG_OOB or MSG_PEEK was set for any AF_UNIX socket. The MSG_OOB ﬂag

is supported only for stream-based TCP SOCK_STREAM sockets. Neither

MSG_PEEK nor MSG_OOB is supported for AF_UNIX sockets.

AF_CCITT only: recv() was issued on a listen() socket.

[ETIMEDOUT] The connection timed out during connection establishment, or due to a transmis-

sion timeout on active connection.

[EWOULDBLOCK] Non-blocking I/O is enabled using

ioctl() FIOSNBIO request, and the

requested operation would block.

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, passing a size_t pointer will evoke compile-time warnings, which must be corrected in order for the

application to behave correctly. Also, 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)).

MULTITHREAD USAGE

The

recv(), recvmsg(), and recvfrom() system calls are thread-safe. They each have a cancella-

tion point; and they are async-cancel safe, async-signal safe, and fork-safe.

AUTHOR

recv(), recvmsg(), and recvfrom() were developed by HP and the University of California, Berke-

ley.