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P4 Virtual File Service Documentation | 2026.1

# check

## Purpose

Query the P4ALTSYNC agent for a workspace root. If the workspace root is not already controlled by the agent, convert it to be controlled by the agent, if possible.

## Input to agent

Key | Value
--- | ---
altSync | `check`
client | The client workspace name
clientRoot | The client root path
port | The P4PORT the client used to connect to the server
user | The P4USER the client used to connect to the server

## Action for the agent to perform

If the P4ALTSYNC agent is running, and the workspace root is either already under the agent’s control, or can be and has been converted to being under the agent’s control, return success. Otherwise send an error to prevent the command from continuing to attempt to use P4ALTSYNC.

## Output from the agent

Key | Value
--- | ---
result | Boolean true for success
error | Description of what went wrong (applicable only if the result is boolean false or the string literal "error")
altSyncVersion | The version of the altSync protocol that the altSync agent understands
agentProgram | The name and version of the altSync agent (optional)

## Example of input and output

Input:

Copy

    {"altSync":"check","client":"vfs-cmr5","clientRoot":"e:\\temp\\vfs\\cmr5","port":"perforce:1666","user":"npoole"}

Output:

    {"result":true,"altSyncVersion":1,"agentProgram":"P4VFS"}

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