# mtell

Returns the offset of the current byte relative to the beginning of a file

## Calling Sequence

    mtell([fd])

## Arguments

fd

  a scalar: a file descriptor returned by the function `mopen`. `-1` stands for last opened file. Default value is `-1`.

## Description

The function `mtell` returns the offset of the current byte relative to the beginning of the file associated with the named stream `fd`.

## Examples

    // Open in binary write a temporary file
    testFile=TMPDIR + '/testFile.bin';
    fd = mopen(testFile,'wb');

    mput(42,'d'); // Will write 42 in last opened file
    mtell() // Will return 8, the current position in the file descriptor

    mput(42+2,'d', fd); // Will open fd transparently to write 42
    mtell(fd) // Will return 16, the current position in the file descriptor

    mseek(0, fd); // return at the beginning of the file
    mtell(fd) // Will return 0

    mclose(fd);

## See Also

- mclose
- meof
- mfprintf
- fprintfMat
- mfscanf
- fscanfMat
- mget
- mgetstr
- mopen
- mprintf
- mput
- mputstr
- mseek
- mdelete