rom/exec/createmsgport.c

   1 /*
   2     Copyright © 1995-2001, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: Create a new message port.
   6     Lang: english
   7 */
   8 #include <exec/memory.h>
   9 #include <exec/ports.h>
  10 #include <exec/execbase.h>
  11 #include <aros/libcall.h>
  12 #include <proto/exec.h>
  13
  14 /*****************************************************************************
  15
  16     NAME */
  17
  18         AROS_LH0(struct MsgPort *, CreateMsgPort,
  19
  20 /*  SYNOPSIS */
  21
  22 /*  LOCATION */
  23         struct ExecBase *, SysBase, 111, Exec)
  24
  25 /*  FUNCTION
  26         Create a new message port. A signal will be allocated and the message
  27         port set to signal you task
  28
  29     INPUTS
  30
  31     RESULT
  32         Pointer to messageport structure
  33
  34     NOTES
  35
  36     EXAMPLE
  37
  38     BUGS
  39
  40     SEE ALSO
  41
  42     INTERNALS
  43
  44 ******************************************************************************/
  45 {
  46     AROS_LIBFUNC_INIT
  47
  48     struct MsgPort *ret;
  49
  50     /* Allocate memory for struct MsgPort */
  51     ret=(struct MsgPort *)AllocMem(sizeof(struct MsgPort),MEMF_PUBLIC|MEMF_CLEAR);
  52     if(ret!=NULL)
  53     {
  54         BYTE sb;
  55
  56         /* Allocate a signal bit */
  57         sb=AllocSignal(-1);
  58         if(sb!=-1)
  59         {
  60             /* Initialize messageport structure. First set signal bit. */
  61             ret->mp_SigBit=sb;
  62
  63             /* Clear the list of messages */
  64             ret->mp_MsgList.lh_Head=(struct Node *)&ret->mp_MsgList.lh_Tail;
  65             /* ret->mp_MsgList.lh_Tail=NULL; */
  66             ret->mp_MsgList.lh_TailPred=(struct Node *)&ret->mp_MsgList.lh_Head;
  67
  68             /* Set port to type 'signalling' */
  69             ret->mp_Flags=PA_SIGNAL;
  70
  71             /* Set port to type MsgPort */
  72             ret->mp_Node.ln_Type = NT_MSGPORT;
  73
  74             /* Finally set task to send the signal to. */
  75             ret->mp_SigTask=SysBase->ThisTask;
  76
  77             /* Now the port is ready for use. */
  78             return ret;
  79         }
  80         /* Couldn't get the signal bit. Free the memory. */
  81         FreeMem(ret,sizeof(struct MsgPort));
  82     }
  83     /* function failed */
  84     return NULL;
  85     AROS_LIBFUNC_EXIT
  86 } /* CreateMsgPort */
  87