Command Messages

Control messages for computer management and connection maintenance. More...

Collaboration diagram for Command Messages:

Variables
const char *const	kMsgCNoop
	No operation command.
const char *const	kMsgCClose
	Close connection command.
const char *const	kMsgCEnter
	Enter computer command.
const char *const	kMsgCLeave
	Leave computer command.
const char *const	kMsgCClipboard
	Clipboard grab notification.
const char *const	kMsgCScreenSaver
	Screensaver state change.
const char *const	kMsgCResetOptions
	Reset options command.
const char *const	kMsgCInfoAck
	Computer information acknowledgment.
const char *const	kMsgCKeepAlive
	Keep-alive message.

Detailed Description

Control messages for computer management and connection maintenance.

Variable Documentation

kMsgCClipboard

const char* const kMsgCClipboard

extern

Clipboard grab notification.

Message Code: "CCLP" Direction: Primary ↔ Secondary Format: "CCLP%1i%4i" Parameters:

• $1: Clipboard identifier (1 byte)
• $2: Sequence number (4 bytes)

Example:

Primary clipboard grabbed, sequence 1

"CCLP\x00\x00\x00\x00\x01"

Sent when an application grabs a clipboard on either computer. This notifies the other computer that clipboard ownership has changed. Secondary computers must use the sequence number from the most recent kMsgCEnter. The primary always sends sequence number 0.

Clipboard Identifiers:

• 0: Primary clipboard (Ctrl+C/Ctrl+V)
• 1: Selection clipboard (middle-click on X11)

See also

kMsgDClipboard

Since

Protocol version 1.0

kMsgCClose

const char* const kMsgCClose

extern

Close connection command.

Message Code: "CBYE" Direction: Primary → Secondary Format: No parameters

Instructs the client to close the connection gracefully. The client should clean up resources and disconnect.

Since

Protocol version 1.0

kMsgCEnter

const char* const kMsgCEnter

extern

Enter computer command.

Message Code: "CINN" Direction: Primary → Secondary Format: "CINN%2i%2i%4i%2i" Parameters:

• $1: Entry X coordinate (2 bytes, signed)
• $2: Entry Y coordinate (2 bytes, signed)
• $3: Sequence number (4 bytes, unsigned)
• $4: Modifier key mask (2 bytes, unsigned)

Example:

Enter at (400, 300), sequence 1, no modifiers

"CINN\x01\x90\x01\x2C\x00\x00\x00\x01\x00\x00"

Sent when the mouse cursor enters the secondary computer from the primary. The coordinates specify the exact entry point. The sequence number is used to order messages and must be returned in subsequent messages from the client. The modifier mask indicates which toggle keys (Caps Lock, Num Lock, etc.) are active and should be synchronized on the secondary computer.

See also

kMsgCLeave

Since

Protocol version 1.0

kMsgCInfoAck

const char* const kMsgCInfoAck

extern

Computer information acknowledgment.

Message Code: "CIAK" Direction: Primary → Secondary Format: No parameters

Sent by the primary in response to a secondary computer's kMsgDInfo message. This acknowledgment is sent for every kMsgDInfo, whether or not the primary had previously sent a kMsgQInfo query.

See also

kMsgDInfo, kMsgQInfo

Since

Protocol version 1.0

kMsgCKeepAlive

const char* const kMsgCKeepAlive

extern

Keep-alive message.

Message Code: "CALV" Direction: Primary ↔ Secondary Format: No parameters

Sent periodically by the server to verify that connections are still active. Clients must reply with the same message upon receipt.

Timing:

• Default interval: 3 seconds (configurable)
• Timeout: 3 missed messages trigger disconnection

Behavior:

• Server sends keep-alive to client
• Client immediately responds with keep-alive back to server
• If server doesn't receive response within timeout, it disconnects client
• If client doesn't receive keep-alives, it should disconnect from server

See also

kKeepAliveRate, kKeepAlivesUntilDeath

Since

Protocol version 1.3

kMsgCLeave

const char* const kMsgCLeave

extern

Leave computer command.

Message Code: "COUT" Direction: Primary → Secondary Format: No parameters

Sent when the mouse cursor leaves the secondary computer and returns to the primary. Upon receiving this message, the secondary computer should:

1. Send clipboard data for any clipboards it has grabbed
2. Only send clipboards that have changed since the last leave
3. Use the sequence number from the most recent kMsgCEnter

See also

kMsgCEnter, kMsgCClipboard

Since

Protocol version 1.0

kMsgCNoop

const char* const kMsgCNoop

extern

No operation command.

Message Code: "CNOP" Direction: Secondary → Primary Format: No parameters

A no-operation message that can be used for testing connectivity or as a placeholder. Has no effect on the receiving end.

Since

Protocol version 1.0

kMsgCResetOptions

const char* const kMsgCResetOptions

extern

Reset options command.

Message Code: "CROP" Direction: Primary → Secondary Format: No parameters

Instructs the client to reset all of its options to their default values. This is typically sent when the server configuration changes.

See also

kMsgDSetOptions

Since

Protocol version 1.0

kMsgCScreenSaver

const char* const kMsgCScreenSaver

extern

Screensaver state change.

Message Code: "CSEC" Direction: Primary → Secondary Format: "CSEC%1i" Parameters:

• $1: Screensaver state (1 byte): 1 = started, 0 = stopped Examples:

Screensaver started

"CSEC\x01"

Screensaver stopped

"CSEC\x00"

Notifies the secondary computer when the primary's screensaver starts or stops. The secondary can use this to synchronize its own screensaver state.

Since

Protocol version 1.0