fsFilePosition (Function)

This will return the position of the FILE data pointer. The function can be used to determine the size of the file in conjunction with fsFileSeek (with offset set to -1). All data is addressed as 8 bit, and after each successful read or write operation, the file data pointer is automatically incremented.

Input:                

fd : FILE

FILE descriptor for the file retrieved from fsFileOpen or fsFileCreate.

Returns: DINT

Position of file pointer.

Declaration:

FUNCTION fsFilePosition : DINT;
VAR_INPUT
  fd : FILE;
END_VAR;

Example:

...
IF fsFileExists(name := "\gpslog.dat") THEN
   fdGpslog := fsFileOpen(name := "\gpslog.dat");
   IF fsFileStatus(fd := fdGpslog) = 0 THEN
      // Is file empty?
      IF fsFilePosition(fd := fdGpslog) > 0 THEN
         rc := fsFileSeek(fd := fsGpslog, offset := 0);
         IF rc = 0 THEN
            // Iterate file
            REPEAT
               // Read data fields
               len1 := fsFileRead(fd := fdGpslog, buffer := ADDR(linsec), length := SIZEOF(linsec));
               len2 := fsFileRead(fd := fdGpslog, buffer := ADDR(lat), length := SIZEOF(lat));
               len3 := fsFileRead(fd := fdGpslog, buffer := ADDR(lon), length := SIZEOF(lon));
               // Is data valid?
               IF len1 = SIZEOF(linsec) AND len2 = SIZEOF(lat) AND len3 = SIZEOF(lon) THEN
                  // Data is read
                  ...
               END_IF;
            UNTIL len1 <> SIZEOF(linsec) OR len2 <> SIZEOF(lat) OR len3 <> SIZEOF(lon)
            END_REPEAT;
         ELSE
            // Error
         END_IF;
      ELSE
         // No data
      END_IF;
      fsFileClose(fd := fdGpslog);
   ELSE
      // Could not open file
   END_IF;
ELSE
   // File dont exist
END_IF;
...