MQL4 Reference File Functions FileFindFirst

FileFindFirst

The function starts the search of files or subdirectories in a directory in accordance with the specified filter.

long  FileFindFirst(
   const string   file_filter,          // String - search filter
   string&        returned_filename,    // Name of the file or subdirectory found
   int            common_flag=0         // Defines the search
   );

Parameters

file_filter

[in] Search filter. A subdirectory (or sequence of nested subdirectories) relative to the \Files directory, in which files should be searched for, can be specified in the filter.

returned_filename

[out] The returned parameter, where, in case of success, the name of the first found file or subdirectory is placed. Only the file name is returned (including the extension), the directories and subdirectories are not included no matter if they are specified or not in the search filter.

common_flag

[in] Flag determining the location of the file. If common_flag = FILE_COMMON, then the file is located in a shared folder for all client terminals \Terminal\Common\Files. Otherwise, the file is located in a local folder.

Return Value

Returns handle of the object searched, which should be used for further sorting of files and subdirectories by the FileFindNext() function, or INVALID_HANDLE when there is no file and subdirectory corresponding to the filter (in the particular case - when the directory is empty). After searching, the handle must be closed using the FileFindClose() function.

Note

For security reasons, work with files is strictly controlled in the MQL4 language. Files with which file operations are conducted using MQL4 means, cannot be outside the file sandbox.

Example:

//--- display the window of input parameters when launching the script
#property script_show_inputs
//--- filter
input string InpFilter="Dir1\\*";
//+------------------------------------------------------------------+
//| Script program start function                                    |
//+------------------------------------------------------------------+
void OnStart()
  {
   string file_name;
   string int_dir="";
   int    i=1,pos=0,last_pos=-1;
//--- search for the last backslash
   while(!IsStopped())
     {
      pos=StringFind(InpFilter,"\\",pos+1);
      if(pos>=0)
         last_pos=pos;
      else
         break;
     }
//--- the filter contains the folder name
   if(last_pos>=0)
      int_dir=StringSubstr(InpFilter,0,last_pos+1);
//--- get the search handle in the root of the local folder
   long search_handle=FileFindFirst(InpFilter,file_name);
//--- check if the FileFindFirst() is executed successfully
   if(search_handle!=INVALID_HANDLE)
     {
      //--- in a loop, check if the passed strings are the names of files or directories
      do
        {
         ResetLastError();
         //--- if it's a file, the function returns true, and if it's a directory, it returns error ERR_FILE_IS_DIRECTORY
         FileIsExist(int_dir+file_name);
         PrintFormat("%d : %s name = %s",i,GetLastError()==ERR_FILE_IS_DIRECTORY ? "Directory" : "File",file_name);
         i++;
        }
      while(FileFindNext(search_handle,file_name));
      //--- close the search handle
      FileFindClose(search_handle);
     }
   else
      Print("Files not found!");
  }