The behaviour of these functions is affected by settings in php.ini.
Here's a short explanation of the configuration directives.
stomp.default_broker
The default broker URI to use when connecting to the message broker if no other URI is specified.
stomp.default_connection_timeout_sec
The seconds part of the default connection timeout.
stomp.default_connection_timeout_usec
The microseconds part of the default connection timeout.
stomp.default_read_timeout_sec
The seconds part of the default reading timeout.
stomp.default_read_timeout_usec
The microseconds part of the default reading timeout.