pSOSystem System Calls - Read

ecvmsg pNA+ System Calls
Return Value
msg_iov Points to an array whose members
(msg_iov[0], ..,msg_iov[msglen-1]) specify
the buffers in which the received data is
stored. The iovec structure has the following
format:
struct iovec {
char *iov_base: /* base address */
int iov_len; /* buffer length */
};
This structure cannot be packed. Each iovec
entry specifies the base address and length of
an area in memory where data is stored.
recvmsg() always fills an area completely
before it goes to the next area.
msg_accrights Points to a buffer that receives the access
rights information sent along with a message.
This applies to messages that a UNIX host
sends.
msg_accrightslen Specifies the length of the buffer pointed to by
msg_accrights.
flags Specifies usage options and is the result of an OR operation performed
on one or more of the following symbolic constants (defined in
). It can also be set to 0.
MSG_OOB Specifies that you want recvmsg() to read
any out-of-band data present on the socket,
rather than the regular in-band data.
MSG_PEEK Specifies that you want recvmsg() to peek at
the data present on the socket; the data is returned,
but not consumed, so that a subsequent
receive operation sees the same data.
This system call returns the number of bytes received, or it returns -1 if an error
occurs. When the receive is shutdown by either end of the connection, a value of 0 is
returned.
4-52 pSOSystem System Calls