DosCwait

This call places the current thread in a wait state until an asynchronous child process ends. When the process ends, its process ID and termination code are returned to the caller.

DosCwait

(ActionCode, WaitOption, ReturnCodes, ProcessIDWord, ProcessID)

ActionCode (USHORT) - input

The process whose termination is being waited for.

Value

Definition
0
The child process indicated by ProcessID.
1
The last descendant of the child process indicated by ProcessID.
WaitOption (USHORT) - input
Return if no child process ends.

Value

Definition
0
Wait if no child process ends or until no child processes are outstanding.
1
Do not wait for child processes to end.

ReturnCodes (PRESULTCODES) - output
Address of the structure containing the termination code and the result code indicating the reason for the child's termination.

codeTerminate (USHORT)

The termination code furnished by the system describing why the child terminated.

Value

Definition
0
EXIT (normal)
1
Hard error abort
2
Trap operation
3
Unintercepted DosKillProcess
codeResult (USHORT)
Result code specified by the terminating process on its last DosExit call.
ProcessIDWord (PPID) - output
Address of the process ID of the ending process.
ProcessID (PID) - input
ID of the process whose termination is being waited for:

Value

Definition
0
Any child process.
<> 0
The indicated child process and all its descendants.
rc (USHORT) - return
Return code descriptions are:
• NO_ERROR 13
  ERROR_INVALID_DATA
  128
  ERROR_WAIT_NO_CHILDREN
  129
  ERROR_CHILD_NOT_COMPLETE
  184
  ERROR_NO_CHILD_PROCESS
  303
  ERROR_INVALID_PROCID
  Remarks

  DosCwait waits for completion of a child process, whose execution is asynchronous to that of its parent process. The child process is created by a DosExecPgm request with ExecFlags=2 specified. If the child process has multiple threads, the result code returned by DosCwait is the one passed to it by the DosExit request that terminates the process.

  DosCwait can also wait for the descendant processes of a child process to complete before it returns. However, it does not report status for descendant processes.

  To wait for all child processes and descendant processes to end, issue DosCwait repeatedly, with ActionCode=1 andProcessID=0 specified, until ERROR_NO_CHILD_PROCESS is returned. The contents of ProcessIDWord can be examined to determine which child the termination codes are from.

  If no child processes were started, DosCwait returns with an error. If no child processes terminate, DosCwait can wait until one terminates before returning to the parent, or it can return immediately if it specifies WaitOption=1. This parameter is used to return the result code of a child process that has already ended.

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