Return the location of the file pointer in a low level file.
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 Syntax

        GT_FTell(<nFileHandle>) --> nBytePosition

 Arguments:

      <nFileHandle> is the handle of a file that has been opened or
      created with one of Clipper's low level file functions.

 Returns:

      The byte position of the file pointer.

 Description:

      GT_FTell() can be used for finding the location or a file
      pointer when working with files opened or created with Clipper's
      low level file functions.

 Examples:

      // Print the location of the file pointer.

      local nFile := fopen("LIFE.42")
      fseek(nFile,41)
      ? GT_FTell(nFile)     // Print the location in the file.
      fclose(nFile)

 Source: FTELL.PRG

 Author:  Dave Pearson