The format of messages from the sac is defined by the structure
sacmsg:
struct sacmsg { int sc_size; /* size of optional data portion */ char sc_type; /* type of message */ };
The sac may send four types of messages to port monitors. The type of message is indicated by setting the sc_type field of the sacmsg structure to one of the following:
SC_STATUS status request SC_ENABLE enable message SC_DISABLE disable message SC_READDB message indicating that the port monitor's _pmtab file should be read
sc_size indicates the size of the optional data part of the message. See "Message Classes". For Solaris, sc_size should always be set to 0.
A port monitor must respond to every message sent by the sac.