The process cannot access file ... being used by another process

Author: MikeCaron

Creation Date: 3/16/2009 11:34 AM

Wealth Lab » WealthScript (.NET) » The process cannot access file ... being used by another process

MikeCaron

3/16/2009 11:34 AM

I could not find a previous topic on this error message, "The process cannot access the file 'c:\tmp\crdt1.txt' because it is being used by another process."

Seems to be some sort of a file synchronization/flushing issue when parsing 839 symbols using the Multisymbol backtest function on EOD data. About 221 unique symbols are being written out to the file. I do a flush of the StreamWriter object, but not the FileStream object.

Any thoughts on how to resolve this problem?

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I could not find a previous topic on this error message, "The process cannot access the file 'c:\tmp\crdt1.txt' because it is being used by another process."

Seems to be some sort of a file synchronization/flushing issue when parsing 839 symbols using the Multisymbol backtest function on EOD data. About 221 unique symbols are being written out to the file. I do a flush of the StreamWriter object, but not the FileStream object.

Any thoughts on how to resolve this problem?

[CODE]using System;
using System.Collections.Generic;
using System.Text;
using System.IO;
using System.Drawing;
using WealthLab;
using WealthLab.Indicators;

namespace WealthLab.Strategies
{
	public class CRDT1 : WealthScript
	{
		/* Create Strategy Parameters */
		private StrategyParameter MAPeriod;
		private /**const*/ bool FORECAST = true;
		
		protected override void Execute()
		{
			//if (FORECAST) {
				FileStream f1 = new FileStream("c:/tmp/crdt1.txt", FileMode.Append, FileAccess.Write);
				StreamWriter sw = new StreamWriter(f1);  				// Create a new stream to write to the file
			//}
			
			DataSeries MA200Cl = SMA.Series(Close, 200);
			DataSeries RSI4 = RSI.Series(Close, 4);
			DataSeries ROC1 = ROC.Series(Close,2);

DataSeries MA20ClVol = SMA.Series(Close*Volume, 20);
			DataSeries MA20LowVol = Lowest.Series(Volume, 20);

for(int bar = 201; bar < Bars.Count; bar++) {
				if (IsLastPositionActive) {
					Position p = LastPosition;
					SellAtClose(bar, p, "EOD Sell");
				} else {
					if (Close[bar] >= 5 && Close[bar] > MA200Cl[bar]){
					if ((RSI4[bar] < 20) && (12000/Close[bar] < MA20LowVol[bar]*0.007) && ROC1[bar] <= -3.0 ) {
						BuyAtLimit(bar + 1, Close[bar]*0.94, "6% down");
						if (FORECAST) {
							StringBuilder sb = new StringBuilder();
							sb.Append(Convert.ToString(Bars.Date[bar]));
							sb.AppendFormat("\t");
							sb.Append(Convert.ToString(bar));
							sb.AppendFormat("\t");
							sb.Append(Bars.Symbol);
							sb.AppendFormat("\t");
							sb.Append(Bars.SecurityName);							
							sb.AppendFormat("\t");
							sb.Append("Buy Next Day at Open");							
							sb.AppendFormat("\t");
							sb.Append(Close[bar]*0.94);							
							sb.AppendFormat("\t");
							sb.Append(RSI2[bar]);							
							if (bar < Bars.Count-1) {
								sb.AppendFormat("\t");
								sb.Append(Open[bar+1]);							
								sb.AppendFormat("\t");
								sb.Append(Low[bar+1]);							
								sb.AppendFormat("\t");
								sb.Append(High[bar+1]);
								sb.AppendFormat("\t");
								sb.Append(Close[bar+1]);
							}
							sb.AppendFormat("\r\n");
							sw.Write(sb.ToString() );
						}
					}
					}
				}
			}
			//if (FORECAST) {
				sw.Flush();
				sw.Close();
				f1.Close();     
			//}
		}
	}
}[/CODE]

DaveAronow

3/16/2009 11:59 AM

Try wrapping the file access in a using block. Google it for more info.

MikeCaron

3/18/2009 8:49 AM

It took some hunting, but thanks for the clue Dave! I am posting the fix in case anyone else stumbles across this problem. It appears that the StreamWriter() call was returning an error. Waiting until it no longer has an error fixed the problem.

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TrendCatcher

3/18/2009 9:21 AM

Hi Mike,
Could you repost the entire script? Thanks.

MikeCaron

3/18/2009 2:13 PM

Here is the updated script:

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Here is the updated script:

[CODE]using System;
using System.Collections.Generic;
using System.Text;
using System.IO;
using System.Drawing;
using WealthLab;
using WealthLab.Indicators;

namespace WealthLab.Strategies
{
	public class MultiSymbolFileOutputTest : WealthScript
	{
		/* Create Strategy Parameters */
		private StrategyParameter MAPeriod;
		private /**const*/ bool FORECAST = true;
		private StreamWriter sw;
		private FileStream f1;
		private int count;
		
		protected override void Execute()
		{

bool haveExclusiveAccess = false;

// Wait for exclusive access to file 
			count=0;
			while (haveExclusiveAccess == false) {
				try {
					f1 = new FileStream("c:/tmp/msfot1.txt", FileMode.Append, FileAccess.Write);  	// 
					haveExclusiveAccess = true;
				}
				catch {
					count++;
					if (count > 100) {
						PrintDebug(Bars.Symbol + ": unable to create FileStream");
						count=0;
					}
					System.Threading.Thread.Sleep(2);
				}
			}
			
			haveExclusiveAccess = false;
			count=0;
			// Wait for exclusive access to file 
			while (haveExclusiveAccess == false) {
				try {
					sw = new StreamWriter(f1);  				// Create a new stream to write to the file
					haveExclusiveAccess = true;
				}
				catch {
					count++;
					if (count > 100) {
						PrintDebug(Bars.Symbol + ": unable to create StreamWriter");
						count=0;
					}
					System.Threading.Thread.Sleep(2);
				}
			}		
			
			DataSeries MA200Cl = SMA.Series(Close, 200);
			DataSeries RSI4 = RSI.Series(Close, 4);
			DataSeries ROC1 = ROC.Series(Close,2);

DataSeries MA20ClVol = SMA.Series(Close*Volume, 20);
			DataSeries MA20LowVol = Lowest.Series(Volume, 20);

for(int bar = 201; bar < Bars.Count; bar++) {
				if (IsLastPositionActive) {
					Position p = LastPosition;
					SellAtClose(bar, p, "EOD Sell");
				} else {
					if (Close[bar] >= 5 && Close[bar] > MA200Cl[bar]){
						if ((RSI4[bar] < 20) && (12000/Close[bar] < MA20LowVol[bar]*0.007) && ROC1[bar] <= -3.0 ) {
							BuyAtLimit(bar + 1, Close[bar]*0.94, "6% down");
							if (FORECAST) {
								StringBuilder sb = new StringBuilder();
								sb.Append(Convert.ToString(Bars.Date[bar]));
								sb.AppendFormat("\t");
								sb.Append(Convert.ToString(bar));
								sb.AppendFormat("\t");
								sb.Append(Bars.Symbol);
								sb.AppendFormat("\t");
								sb.Append(Bars.SecurityName);							
								sb.AppendFormat("\t");
								sb.Append("Buy Next Day at Open");							
								sb.AppendFormat("\t");
								sb.Append(Close[bar]*0.94);							
								sb.AppendFormat("\t");
								sb.Append(RSI4[bar]);							
								if (bar < Bars.Count-1) {
									sb.AppendFormat("\t");
									sb.Append(Open[bar+1]);							
									sb.AppendFormat("\t");
									sb.Append(Low[bar+1]);							
									sb.AppendFormat("\t");
									sb.Append(High[bar+1]);
									sb.AppendFormat("\t");
									sb.Append(Close[bar+1]);
								}
								sb.AppendFormat("\r\n");
								sw.Write(sb.ToString() );
							}
						}
					}
				}
			}
			//if (FORECAST) {
			sw.Flush();
			sw.Close();
			f1.Close();     
			//}
		}
	}
}[/CODE]

Wealth Lab » WealthScript (.NET) » The process cannot access file ... being used by another process