====== TimerMsgAfterDelayVBL ======

Sends a message after the specified number of VBLs occur.

==== Synopsis ====

''%%TimerHandle TimerMsgAfterDelayVBL (Item msgport, uint32 fields, uint32 userdata1, uint32 userdata2)%%''

==== Description ====

This function creates a timer that notifies you by message after the specified number of VBLs have occurred. The timer is a one-shot; after sending a notification message the timer enters a suspended state. Use ''%%TimerReset()%%'' to reactivate the timer using new time values, ''%%TimerRestart()%%'' to start another delay period of the same length as last time, or ''%%TimerCancel()%%'' to delete the timer.

The TimerServices thread must be active before calling this function.

==== Arguments ====

  * **msgport** Port to which the notification message is sent.

  * **fields** Number of VBLs to occur before sending the message.

  * **userdata1** Value passed back to you in the msg_DataPtr field of the notification message.

  * **userdata2** Value passed back to you in the msg_DataSize field of the notification message.

==== Return Value ====

A TimerHandle (a positive value) on success or a negative error code.

==== Implementation ====

Library call implemented in lib3do.lib.

==== Associated Files ====

lib3do.lib, timerutils.h

==== See Also ====

''%%TimerMsgAtTimeVBL%%'', [[:documentation:development:opera:pf25:ppgfldr:smmfldr:ldofldr:01ldo186#xref29040|TimerMsgHeartbeatVBL]]