fsFilePosition (Function)

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Architecture:

X32 / NX32 / NX32L

Device support:

All

Firmware version:

1.00 / 1.00.00


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;
...