Description: For indirect proxies, returns a new proxy with the specified timeout. ...
Ice 3.1.1 Manual, Page 818:
Description: Returns a new proxy with the given timeout value in milliseconds.
There is a better explanation of what this function does in the "Ice.Default.LocatorCacheTimeout" entry:
Specifies the default locator cache timeout for indirect proxies. If num is set to a value larger than zero, locator cache entries older than num seconds will be ignored. If set to 0, the locator cache won't be used. If set to -1, locator cache entries won't expire.
Each entry in the client-side "locator cache" has an associated timestamp, and when you invoke on an indirect proxy, Ice checks this timestamp against the "locator cache timeout" of the proxy to see if can use the cached entry or if it needs to resolve the indirect proxy using the (remote) Locator.