rom/exec/createiorequest.c

   1 /*
   2     Copyright © 1995-2001, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: Create an I/O request.
   6     Lang: english
   7 */
   8 #include "exec_intern.h"
   9 #include <exec/io.h>
  10 #include <exec/ports.h>
  11 #include <exec/memory.h>
  12 #include <aros/libcall.h>
  13 #include <proto/exec.h>
  14
  15 /*****************************************************************************
  16
  17     NAME */
  18
  19         AROS_LH2(struct IORequest *, CreateIORequest,
  20
  21 /*  SYNOPSIS */
  22         AROS_LHA(struct MsgPort *, ioReplyPort, A0),
  23         AROS_LHA(ULONG,            size,        D0),
  24
  25 /*  LOCATION */
  26         struct ExecBase *, SysBase, 109, Exec)
  27
  28 /*  FUNCTION
  29         Create an I/O request structure bound to a given messageport.
  30         I/O requests are normally used to communicate with exec devices
  31         but can be used as normal messages just as well.
  32
  33     INPUTS
  34         ioReplyPort - Pointer to that one of your messageports where
  35                       the messages are replied to. A NULL port is legal
  36                       but then the function fails always.
  37         size        - Size of the message structure including the struct
  38                       IORequest header. The minimal allowable size is that
  39                       of a struct Message.
  40
  41     RESULT
  42         Pointer to a new I/O request structure or NULL if the function
  43         failed.
  44
  45     NOTES
  46
  47     EXAMPLE
  48
  49     BUGS
  50
  51     SEE ALSO
  52
  53     INTERNALS
  54
  55 ******************************************************************************/
  56 {
  57     AROS_LIBFUNC_INIT
  58
  59     struct IORequest *ret=NULL;
  60
  61     /* A NULL ioReplyPort is legal but has no effect */
  62     if(ioReplyPort==NULL)
  63         return NULL;
  64
  65     /* Allocate the memory */
  66     ret=(struct IORequest *)AllocMem(size,MEMF_PUBLIC|MEMF_CLEAR);
  67
  68     if(ret!=NULL)
  69     {
  70         /* Initialize it. */
  71         ret->io_Message.mn_ReplyPort=ioReplyPort;
  72
  73         /* This size is needed to free the memory at DeleteIORequest() time. */
  74         ret->io_Message.mn_Length=size;
  75     }
  76
  77     /* All done. */
  78     return ret;
  79     AROS_LIBFUNC_EXIT
  80 } /* CreateIORequest */
  81