Metrologic Optimus R, Руководство по программированию

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Chapter 3 Terminal Specific Function Library 151
The name is a result parameter that is filled in with the address of the
connecting entity, as known to the communications layer. The exact
format of the
name
parameter is determined by the address family in
which the communication is occurring.
The namelen is a value-result parameter; it initially contains the amount of
space pointed to by name ; on return, it will contain the actual length, in
bytes, of the address returned. The
name
is truncated if the buffer provided
is too small. (?)
Return If successful, it returns 0.
On error, it returns -1.
The global variable errno is set to indicate the error condition encountered.
See Also bind, connect, getpeername
getsockopt
Purpose
To get options on a socket.
Syntax int getsockopt (SOCKET s, int level, int optname, char *optval, int *optlen);
s Descriptor identifying a socket.
level Level at which the option resides:
SOL_SOCKET, IPPROTO_TCP, or IPPROTO_IP
optname Socket option for which the value is to be retrieved.
optval Pointer to the buffer in which the value for the requested
option is to be returned.
optlen Pointer to the size of the optval buffer, in bytes.
Example (?)
Description
This routine retrieves the current value for a socket option associated with a
socket of any type, in any state, and stores the result in
optval .
Although options may exist at multiple protocol levels, they are always present
at the uppermost socket level. Options affect socket operations, such as the
packet routing and OOB data transfer.
To manipulate options at the socket level, level is specified as
SOL_SOCKET.
To manipulate options at any other level, the protocol number of the
appropriate protocol controlling the option is supplied.
For example, the following options are recognized:
level = SOL_SOCKET
SO_DEBUG Enables recording of debugging information
SO_REUSEADDR Enables local address reuse
SO_KEEPALIVE Enables sending keep-alives