DosTimerStart

This call starts a periodic interval timer that runs asynchronously to the thread issuing the request. The semaphore is continually cleared at the specified time interval until the timer is turned off by DosTimerStop.

DosTimerStart

(TimeInterval, SemHandle, Handle)

TimeInterval (ULONG) - input

Number of milliseconds (rounded up to the next clock tick) that passes before the semaphore is cleared.
SemHandle (HSEM) - input
Handle of the system semaphore used to communicate the time out to the calling thread. This semaphore should be set by DosSemSet before the next clear by the timer.
Handle (PHTIMER) - output
Address of the timer handle. This handle may be passed to DosTimerStop to stop the periodic timer.
rc (USHORT) - return
Return code descriptions are:
• NO_ERROR 323
  ERROR_TS_SEMHANDLE
  324
  ERROR_TS_NOTIMER
  Remarks

  DosTimerStart allows a timer to start and run asynchronously to a thread. A timer interval is canceled by using the timer handle in the DosTimerStop call. This prevents the semaphore indicated in the DosTimerStart call from being sent notifications.

  The application detects the expirations of the timer when the semaphore is set prior to the next expiration of the timer. When an application waits for this semaphore to clear, more than one clearing of the timer may occur before the application resumes execution. If it is necessary to determine the actual elapsed time, the Global Information Segment milliseconds field can be saved by a DosGetInfoSeg request before calling DosTimerStart. This saved value is compared to the current value when the process resumes.

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