MailBoxes

• Used to send pointers to application specific data structures to waiting tasks.
• Initialize with 0.
• One can also use a mailbox to control access to a single resource like a binary semaphore.
• Initialize it with a pointer to the resource.

OSMboxCreate

OS_EVENT *OSMboxCreate(void *pmsg);

OSMboxDel

OS_EVENT *OSMboxDel(OS_EVENT *pevent, INT8U opt, INT8U *perr);

OSMboxPend

void *OSMboxPend(OS_EVENT *pevent, INT16U timeout, INT8U *perr);

OSMboxPendAbort

INT8U OSMboxPendAbort(OS_EVENT *pevent, INT8U opt, INT8U *perr);

OSMboxAccept

void *OSMboxAccept(OS_EVENT *pevent);

OSMboxPost

INT8U OSMboxPost(OS_EVENT *pevent, void *pmsg);

OSMboxPostOpt

INT8U OSMboxPostOpt(OS_EVENT *pevent, void *pmsg, INT8U opt);

• A more powerful version of post.
• Takes an option:
  • NULL for no option. Behaves just like OSMboxPost()
  • OS_POST_OPT_BROADCAST
• With no option only the highest waiting taks gets the message and its made ready to run.
• If there are no waiting tasks, then the message is set in the ECB and the function returns.
• If a task was made ready the ECB will be cleared and the scheduler will be called.
• It is an error to post to the mailbox if it already has data

OSMboxQuery

INT8U OSMboxQuery(OS_EVENT *pevent, OS_MBOX_DATA *p_mbox_data);