FTELL File Position Function

Section: Input/Ouput Functions

Usage

Returns the current file position for a valid file handle. The general use of this function is 
  n = ftell(handle)

The handle argument must be a valid and active file handle. The return is the offset into the file relative to the start of the file (in bytes).

Example

Here is an example of using ftell to determine the current file position. We read 512 4-byte floats, which results in the file pointer being at position 512*4 = 2048. 
--> fp = fopen('test.dat','wb');
--> fwrite(fp,randn(512,1));
--> fclose(fp);
--> fp = fopen('test.dat','rb');
--> x = fread(fp,[512,1],'float');
--> ftell(fp)

ans = 
 2048