In some situations a p4 procedure will give an error message and then exit. This is typically done as a result of a failed system call and handled by calling the p4 procedure named p4_error that examines the return values from socket procedures, etc. Most of the time however, the procedures simply return a value. Some of the procedures return no value and thus are declared to return VOID. Some of the procedures return either a pointer to a character string or NULL; NULL indicates an error. The remaining procedures return an integer value; (-1) indicates an error.
Functions for Process Management,Functions for Cluster Management, ,p4 Functions for Managing Processes and Clusters