long lseek (int fd, long offset, int flag);
flag is one of:
The offset is set to offset bytes.
The offset is set to its current location plus offset bytes.
The offset is set to the size of the file plus offset bytes.
On success, the resulting unsigned offset in bytes from the beginning of the file is returned. Otherwise, a value of -1 is returned.
fd is not a valid open file descriptor.
fd is associated with the GDB console.
flag is not a proper value.
The call was interrupted by the user.