This is the simplest method of using an operation offered by a published Web Service:
fgl_ws_call("service name", "port name", "operation", [parameters])
In order to use this function properly, the 4GL developer must know beforehand the expected input and output. This is because there is no error information returned should the service fail to execute. It will always return the expected return values, if these return values are missing or incorrect then they will be replaced by NULL values. The function requires the service name, the port name, the specific operation name and, optionally, any input parameters. This information is required in order to pinpoint a unique operation:
CALL fgl_ws_call("Web_Service_Simple", "Simple", "add", 2, 3)