rom/exec/childstatus.c

   1 /*
   2     Copyright © 1995-2007, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Find out the status of a child task.
   6 */
   7 #include "exec_intern.h"
   8 #include <proto/exec.h>
   9
  10 /*****************************************************************************
  11
  12     NAME */
  13
  14         AROS_LH1(ULONG, ChildStatus,
  15
  16 /*  SYNOPSIS */
  17         AROS_LHA(ULONG, tid, D0),
  18
  19 /*  LOCATION */
  20         struct ExecBase *, SysBase, 125, Exec)
  21
  22 /*  FUNCTION
  23         Return the status of a child task. This allows the Task to
  24         determine whether a particular child task is still running or not.
  25
  26     INPUTS
  27         tid     --  The ID of the task to examine. Note that this is _NOT_
  28                     a task pointer.
  29
  30     RESULT
  31         One of the CHILD_* values.
  32
  33     NOTES
  34         This function will work correctly only for child tasks that are
  35         processes created with NP_NotifyOnDeath set to TRUE. Otherwise
  36         it may report CHILD_NOTFOUND even if child already exited.
  37
  38     EXAMPLE
  39
  40     BUGS
  41
  42     SEE ALSO
  43
  44     INTERNALS
  45
  46 *****************************************************************************/
  47 {
  48     AROS_LIBFUNC_INIT
  49
  50     struct Task     *this;
  51     struct ETask    *et;
  52     struct ETask    *child;
  53     ULONG            status = CHILD_NOTFOUND;
  54
  55     this = FindTask(NULL);
  56     if ((this->tc_Flags & TF_ETASK) == 0)
  57         return CHILD_NOTNEW;
  58
  59     et = this->tc_UnionETask.tc_ETask;
  60
  61     /* Sigh... */
  62     Forbid();
  63
  64     /* Search through the running tasks list */
  65     ForeachNode(&et->et_Children, child)
  66     {
  67         if (child->et_UniqueID == tid)
  68         {
  69             status = CHILD_ACTIVE;
  70             break;
  71         }
  72     }
  73
  74     ForeachNode(&et->et_TaskMsgPort.mp_MsgList, child)
  75     {
  76         if (child->et_UniqueID == tid)
  77         {
  78             status = CHILD_EXITED;
  79             break;
  80         }
  81     }
  82
  83     Permit();
  84     return status;
  85
  86     AROS_LIBFUNC_EXIT
  87 } /* ChildStatus */