DosFlagProcess

This call allows one process to set an external event flag for another.

DosFlagProcess

(ProcessID, ActionCode, Flagnum, Flagarg)

ProcessID (PID) - input

ID of the process or root process of the process tree, who is to receive notification that the flag event has occurred.
ActionCode (USHORT) - input
Indicates who is to receive notification that the flag event has occurred.

Value

Definition
0
The indicated process and all its descendant processes are flagged. (Detached processes cannot be flagged.) The indicated process must be the current process or one it has created as a non-detached process. If the indicated process terminates, its descendants are still flagged.
1
Only the indicated process is flagged. Any process can be specified.
Flagnum (USHORT) - input
Number of the flag event whose occurrence is to be signalled as shown below:

Value

Definition
0
Flag A
1
Flag B
2
Flag C.
Flagarg (USHORT) - input
An argument passed to indicated processes.
rc (USHORT) - return
Return code descriptions are:
• NO_ERROR 1
  ERROR_INVALID_FUNCTION
  156
  ERROR_SIGNAL_REFUSED
  186
  ERROR_INVALID_FLAG_NUMBER
  303
  ERROR_INVALID_PROCID
  Remarks

  A process issues DosFlagProcess to set one of three user-defined flags available to the process. The meaning of the flag is defined by the flag user - the process that receives the signal generated by the OS/2 signal mechanism upon the setting of the flag.

  When the flag user is signaled, its reaction to the signal depends on values it has specified with DosSetSigHandler. For example, it can respond by giving control to a signal handler it has registered with DosSetSigHandler for the signal that corresponds to the user flag (SIGPFA corresponds to Flag A, and so on). Or, the flag user can ignore the signal and return an error code to the flagger.

  If no action is specified with DosSetSigHandler by a process for a user flag, the default is to ignore the signal.

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