_C

Retry function for interface fault tolerance handling.

    
    
    
_C(pfn)

    
    
    
_C(pfn, ...args)

Examples

• For fault tolerance of functions without parameters:

  • javascript
  • python
  • cpp

  
      javascript
      
      
  function main(){
      var ticker = _C(exchange.GetTicker)
      // Adjust the retry interval of _C() function to 2 seconds
      _CDelay(2000)
      var depth = _C(exchange.GetDepth)
      Log(ticker)
      Log(depth)
  }
  

  
      python
      
      
  def main():
      ticker = _C(exchange.GetTicker)
      _CDelay(2000)
      depth = _C(exchange.GetDepth)
      Log(ticker)
      Log(depth)
  

  
      c++
      
      
  void main() {
      auto ticker = _C(exchange.GetTicker);
      _CDelay(2000);
      auto depth = _C(exchange.GetDepth);
      Log(ticker);
      Log(depth);
  }
  

• For fault tolerance of functions with parameters:

  • javascript
  • python
  • cpp

  
      javascript
      
      
  function main(){
      var records = _C(exchange.GetRecords, PERIOD_D1)
      Log(records)
  }
  

  
      python
      
      
  def main():
      records = _C(exchange.GetRecords, PERIOD_D1)
      Log(records)
  

  
      c++
      
      
  void main() {
      auto records = _C(exchange.GetRecords, PERIOD_D1);
      Log(records);
  }
  

• Can also be used for fault tolerance handling of custom functions:

  • javascript
  • python
  • cpp

  
      javascript
      
      
  var test = function(a, b){
      var time = new Date().getTime() / 1000
      if(time % b == 3){
          Log("Condition met!", "#FF0000")
          return true
      }
      Log("Retrying!", "#FF0000")
      return false
  }
  
  function main(){
      var ret = _C(test, 1, 5)
      Log(ret)
  }
  

  
      python
      
      
  import time
  def test(a, b):
      ts = time.time()
      if ts % b == 3:
          Log("Condition met!", "#FF0000")
          return True
      Log("Retrying!", "#FF0000")
      return False
  
  def main():
      ret = _C(test, 1, 5)
      Log(ret)
  

  
      c++
      
      
  // C++ does not support this method for custom function fault tolerance

Returns

Arguments

Remarks

The _C() function will continuously call the specified function until it returns successfully (it will retry calling pfn when the function referenced by parameter pfn returns null or false).

For example _C(exchange.GetTicker). The default retry interval is 3 seconds. You can call the _CDelay() function to set the retry interval.

For example _CDelay(1000) means changing the retry interval of the _C() function to 1 second.

The following functions can be (but are not limited to) handled for fault tolerance:

• exchange.GetTicker()
• exchange.GetDepth()
• exchange.GetTrades()
• exchange.GetRecords()
• exchange.GetAccount()
• exchange.GetOrders()
• exchange.GetOrder()
• exchange.GetPositions()

All the above functions can be called through the _C() function to achieve fault tolerance. The _C() function is not limited to fault tolerance for the above functions. The parameter pfn is a function reference, not a function call. Note that you should use _C(exchange.GetTicker) instead of _C(exchange.GetTicker()).