struct MsgPort

#include <exec/io.h>

struct MsgPort
{
    struct Node mp_Node;
    UBYTE   mp_Flags;
    UBYTE   mp_SigBit;          /* signal bit number    */
    void   *mp_SigTask;         /* object to be signalled */
    struct List mp_MsgList;    /* message linked list  */
};

#define mp_SoftInt mp_SigTask   /* Alias */

/* mp_Flags: Port arrival actions (PutMsg) */
#define PF_ACTION       3       /* Mask */
#define PA_SIGNAL       0       /* Signal task in mp_SigTask */
#define PA_SOFTINT      1       /* Signal SoftInt in mp_SoftInt/mp_SigTask */
#define PA_IGNORE       2       /* Ignore arrival */