**CIGAL Reference Manual, Chapter 6 (RealTime): r_repeat**
===== r_repeat -- Begin a loop of repeated operations =====
**usage: r_repeat opflg eflag ltime NRepeats Interval [Flag IntvlFlag]**

R_REPEAT is a REALTIME operator.  It indicates the beginning of a
block of operations that is to be executed more than once (the end of
the block is identified by a corresponding R_END operator).

The number of times the block is repeated is specified by NREPEATS; this
is a long value and must be greater than zero or else the block is never
executed. If NREPEATS is omitted the REPEAT block will cycle indefinitely.
INTERVAL is also a long value; it specifies the amount of time (in 20 usec
ticks) that must elapse between the start of one repeat cycle and the start
of the next.  If INTERVAL is omitted the cycle repeats as fast as possible.

An important feature of R_REPEAT is that blocks of repeated code can be
executed synchronously or asynchronously.  In addition, different blocks of code can be set to display in different screen windows. These features are controlled
by the value of FLAG as follows:
  0 - (Default) R_REPEAT executes SYNCHRONOUSLY. For synchronous execution
      the next operator after the end of the block is not executed until
      the block has finished all of its cycles.
  1 - the block is executed asynchronously. This means that the REALTIME
      processor starts a new parallel processing stream to execute the
      R_REPEAT block, and at the same time the original processing stream
      continues to execute the operators that appear after the block.
  2 - the block is executed asynchronously as above; it is also excluded
      from consideration by the R_SYNCH operator, which can otherwise be
      used to synchronize the execution of asynchronous blocks.
  4 - this block should be started using RT display screen 2, if available.
      Screens are controlled by the RT1RECT, RT2RECT matrices.
      They are usually set to a physical monitor screens SCR1RECT, SCR2RECT.

INTVLFLAG is a bit flag used for controlling interval timing options as:
  1 - the specified INTERVAL is to be treated as a minimum cycle time. If
      one cycle is delayed for any reason the next cycle will still take
      INTERVAL time to complete. Otherwise, the INTERVAL is treated as an
      absolute timer so that is one cycle is delayed subsequent cycles
      will execute more quickly in order to try and complete all NREPEATS
      cycles within the specified time (NREPEATS * INTERVAL).
  2 - the INTERVAL argument is a long array variable specifying different
      time intervals for each cycle.  The INTERVAL pointer is incremented
      by 4 bytes after each cycle.

**See Also:**\\
[[jvs:cigal|CIGAL Home]], 
[[jvs:cigal:manual|CIGAL Manual]], 
[[jvs:cigal:manual:chapter6|RealTime List]], 
[[jvs:cigal:manual:help|Manual Help]]