FileOpen

[Mary Ann Thompson]

/ void OnStart()   { //--- incorrect file opening method    string terminal_data_path=TerminalInfoString(TERMINAL_DATA_PATH);    string filename=terminal_data_path+"\\MQL4\\Files\\"+"fractals.csv";    int filehandle=FileOpen(filename,FILE_WRITE|FILE_CSV);    if(filehandle<0)      {       Print("Failed to open the file by the absolute path ");       Print("Error code ",GetLastError());      } //--- correct way of working in the "file sandbox"    ResetLastError();    filehandle=FileOpen("fractals.csv",FILE_WRITE|FILE_CSV);    if(filehandle!=INVALID_HANDLE)      {       FileWrite(filehandle,TimeCurrent(),Symbol(), EnumToString(ENUM_TIMEFRAMES(_Period)));       FileClose(filehandle);       Print("FileOpen OK");      }    else Print("Operation FileOpen failed, error ",GetLastError()); //--- another example with the creation of an enclosed directory in MQL4\Files\    string subfolder="Research";    filehandle=FileOpen(subfolder+"\\fractals.txt",FILE_WRITE|FILE_CSV);       if(filehandle!=INVALID_HANDLE)      {       FileWrite(filehandle,TimeCurrent(),Symbol(), EnumToString(ENUM_TIMEFRAMES(_Period)));       FileClose(filehandle);       Print("The file most be created in the folder "+terminal_data_path+"\\"+subfolder);      }    else Print("File open failed, error ",GetLastError()); } The above code refers to FileOpen , In the case of Historical data, is there a way of extracing  ohlc data from MT4 programmatically .Thanks

[Fernando Carreiro]

Mary A Thompson: In the case of Historical data, is there a way of extracing  ohlc data from MT4 programmatically?

Yes!

• Timeseries and Indicators Access - MQL4 Reference

[William Roeder]

Mary A Thompson:

string terminal_data_path=TerminalInfoString(TERMINAL_DATA_PATH);    string filename=terminal_data_path+"\\MQL4\\Files\\"+"fractals.csv";    int filehandle=FileOpen(filename,FILE_WRITE|FILE_CSV);

You don't specify the path, /Files is implicit.

File Write Problem (Error: 5002) - Expert Advisors and Automated Trading - MQL5 programming forum #1-2 (2020)
and FolderDelete using TERMINAL_DATA_PATH - General - MQL5 programming forum (2017)

[Fernando Carreiro]

William Roeder #: You don't specify the path, /Files is implicit. File Write Problem (Error: 5002) - Expert Advisors and Automated Trading - MQL5 programming forum #1-2 (2020) and FolderDelete using TERMINAL_DATA_PATH - General - MQL5 programming forum (2017)

@William Roeder, the above code is not the OP's. It is code quoted from the FileOpen documentation example (to explain that very fact you have commented on).