Metrologic Optimus R, Руководство по программированию

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168 "C" Programming Guide For Optimus S/R
Return If connected, it returns a non-zero value.
Otherwise, it returns 0.
See Also Nopen
socket_keepalive
Purpose To set the dummy sending period for a connection.
Syntax int socket_keepalive (int conno, unsigned long val);
int conno; /* connection number */
unsigned long val; /* dummy sending period in milli-second;
set to 0 to disable dummy sending */
Example val = socket_keepalive (conno, p);
Description
In some special application, the remote end will auto-disconnect if it never
receives any packet in a certain period of time. This function will send an
empty packet to the remote end to avoid such problem. (TCP only)
Return If successful, it returns 0.
On error, it returns a negative value. (?)
See Also
socket_noblock
Purpose To set the connection for non-blocking operation.
Syntax int socket_noblock (int conno);
int conno; /* connection number */
Example socket_noblock (conno)
Description This function sets non-blocking operation.
When in non-blocking operation, calls to network functions, which normally
have to wait for network activity to be completed, will return the negative value
EWOULDBLOCK when such a condition is encountered.
Return If successful, it returns 0.
On error, it returns a negative value. (?)
See Also
socket_block
socket_push
Purpose To set the PSH flag on the next outgoing TCP segment.