public final class ChannelAccessConstants extends Object
ChannelAccessCommand
,
ChannelAccessVersion
Modifier and Type | Field and Description |
---|---|
static int |
DEFAULT_REPEATER_PORT
Default UDP port used by repeaters.
|
static int |
DEFAULT_SERVER_PORT
Default TCP and UDP port used by servers.
|
static int |
LARGE_HEADER_SIZE
Size of a large Channel Access header (in bytes).
|
static int |
MAX_CHANNEL_NAME_BYTES_LENGTH
Size limit for a channel name.
|
static short |
MAX_PRIORITY
Maximum (highest) priority for a Channel Access TCP connection.
|
static int |
MESSAGE_SIZE_ALIGNMENT
Number of bytes a Channel Access message must be aligned to (including
the header).
|
static short |
MIN_PRIORITY
Minimum (lowest) priority for a Channel Access TCP connection.
|
static int |
STANDARD_HEADER_SIZE
Size of a standard Channel Access header (in bytes).
|
public static final short MIN_PRIORITY
public static final short MAX_PRIORITY
public static final int STANDARD_HEADER_SIZE
LARGE_HEADER_SIZE
,
Constant Field Valuespublic static final int LARGE_HEADER_SIZE
STANDARD_HEADER_SIZE
,
Constant Field Valuespublic static final int MESSAGE_SIZE_ALIGNMENT
public static final int MAX_CHANNEL_NAME_BYTES_LENGTH
Size limit for a channel name. We could fit a longer name into a message, however, if the message is transferred using UDP, the packet size is rather limited. Due to limitations of the EPICS IOC, channel names that are longer than about 100 bytes rarely exist anyway. The size of 488 bytes (including the terminating null-byte) ensures that at least two search messages fit into a single UDP packet, if the UDP packet has the maximum size of 1024 bytes that is allowed by the protocol.
Please note that there is no guarantee that a message with a channel name of this size can be send via UDP: If the UDP send buffer is smaller, the maximum UDP packet size and thus the limit for the maximum length of a channel name can be smaller.
public static final int DEFAULT_SERVER_PORT
public static final int DEFAULT_REPEATER_PORT
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