Export price history to CSV file on new bar

How - without your code?

The snippets can be found in the above URL, but here is what I have. Sorry for the horrible formatting.

 

int start()

{
   IsNewBar();

}



// Create an array with all the info you need and write to excel

void WriteToExcel(string fileName, double arrayToWrite[]) 
{
   int handle = FileOpen(fileName, FILE_CSV|FILE_WRITE|FILE_READ, ',');
   for(int i = 0; i < ArraySize(arrayToWrite); i++) FileWrite(handle, arrayToWrite[i]);
   FileClose(handle);

   return;
}


bool IsNewBar()
{
   //each tick, check if it's a new 1 hour candle

   static datetime barTime;
   bool result = false;
   
   if(barTime != iTime(NULL,PERIOD_M1,0))
   {
      barTime = iTime(NULL,PERIOD_M1,0);  
     //you'll need to create a function to populate arrOHLCV     
     WriteToExcel("myHistory.csv", arrOHLCV[]);
     result = true;
   }
   
   return(result);
}

That is only an example to demonstrate to write quotes to an csv-file. You have to write (or find by google) the part how to define that array and fill it properly.

Here it is updated. I also changed arrOHLCV to double type because I have no idea why it was a string in the original example. I'm still getting the "'arrOHLCV' - parameter conversion not allowed" error, and i'm getting two warnings:

 

arrays passed by reference only

not all control paths return a value

double arrOHLCV[];


int start()

{
   IsNewBar();

}



// Create an array with all the info you need and write to excel

void WriteToExcel(string fileName, double arrayToWrite[]) 
{
   int handle = FileOpen(fileName, FILE_CSV|FILE_WRITE|FILE_READ, ',');
   for(int i = 0; i < ArraySize(arrayToWrite); i++) FileWrite(handle, arrayToWrite[i]);
   FileClose(handle);

   return;
}


bool IsNewBar()
{
   //each tick, check if it's a new 1 hour candle

   static datetime barTime;
   bool result = false;
   
   if(barTime != iTime(NULL,PERIOD_M1,0))
   {
      barTime = iTime(NULL,PERIOD_M1,0);  
     //you'll need to create a function to populate arrOHLCV     
     WriteToExcel("myHistory.csv", arrOHLCV[100]);
     result = true;
   }
   
   return(result);
}

1) Your array has size 0 you need to ArrayResize() your arrOHLC[].

2) I don't see how and where it gets its values.

Because your code seems very odd to me, I am not sure if you know more than me or that you are doing it wrong.

First of all I think that your function header/parameters

void WriteToExcel(string fileName, double arrayToWrite[]

 should be

void WriteToExcel(string fileName, double &arrayToWrite[]

 Also, your function call

WriteToExcel("myHistory.csv", arrOHLCV[100]);

 The array should already be sized and given values, so the call should be

WriteToExcel("myHistory.csv", arrOHLCV);

I had to just set arrOHLCV to a fixed size because ArrayResize() was returning a "declaration without type" error. Otherwise, there are no other errors. I tried to backtest with 1 minute bars (as markets are currently closed) and it is not writing the file "myHistory.csv" under any MT4 directory that I can see. Is it possible that it is not writing to CSV because I am backtesting? All I want to do is create a CSV file that will update with OHLC data as each new bar comes in. If someone can show me how I can modify the below code to do this it would be appreciated.

 

double arrOHLCV[10000];



int start()

{
   IsNewBar();

}



// Create an array with all the info you need and write to excel

void WriteToExcel(string fileName, double &arrayToWrite[])
{
   int handle = FileOpen(fileName, FILE_CSV|FILE_WRITE|FILE_READ, ',');
   for(int i = 0; i < ArraySize(arrayToWrite); i++) FileWrite(handle, arrayToWrite[i]);
   FileClose(handle);

   return;
}


bool IsNewBar()
{
   //each tick, check if it's a new 1 hour candle

   static datetime barTime;
   bool result = false;
   
   if(barTime != iTime(NULL,PERIOD_M1,0))
   {
      barTime = iTime(NULL,PERIOD_M1,0);  
     //you'll need to create a function to populate arrOHLCV     
     WriteToExcel("myHistory.csv", arrOHLCV);
     result = true;
   }
   
   return(result);
}

I've not done a lot of work with files, but I do remember an EA that I wrote some time ago wrote to a file correctly when attached to a chart, but did not write the file when in the strategy tester. So that may be your problem. Best to test it on a chart next week.