FileOpen returns -1

[WOODY]

Hello,

I am trying to retrieve a simple double value from a "data.txt" file in the following function.
However the FileOpen() function always returns -1 (INVALID_HANDLE).

The "data.txt" only contains 1 value (i.e. 89.55) and is located at MQL4/Files.

double ReadNumberFromFile()
{
   int file_handle;   
   double val;
   file_handle = FileOpen("data.txt",FILE_READ|FILE_TXT);
   Print(file_handle);
   val = FileReadDouble(file_handle);
   FileClose(file_handle);
      
   return val;
}

  

So is the file in a wrong directory or something?
Does anyone have an idea of whats wrong?

Thanks in advance

 

Woody 

[Keith Watford]

Make sure that you do not have the file open when running the code.

Otherwise you will need to use at least one of the SHARE flags

[William Roeder]

Woody: So is the file in a wrong directory or something?

1. Verify it's in the <DataDirectory>MQL4\files or <DataDirectory>\tester\files depending on live vs. tester.
   Data Structure in MetaTrader 4 Build 600 and Higher - MQL4 Articles 17.02.2014
2. Don't just check the return code capture the last error also.
   What are Function return values ? How do I use them ? - MQL4 forum and Common Errors in MQL4 Programs and How to Avoid Them - MQL4 Articles

   4100	ERR_SOME_FILE_ERROR	Some file error
   4101	ERR_WRONG_FILE_NAME	Wrong file name
   4102	ERR_TOO_MANY_OPENED_FILES	Too many opened files
   4103	ERR_CANNOT_OPEN_FILE	Cannot open file
   4104	ERR_INCOMPATIBLE_FILEACCESS	Incompatible access to a fil