Underflow of unsigned int

Some unsigned int are initialized to value -1 e.g.: MemBlock.hpp#L145

  void reset() noexcept {
    m_fileid = -1;
    m_fileBlock = -1;
    m_fSeq = -1;
    m_tapeFileBlock = -1;
    m_payload.reset();
    
    //delete the previous m_context (if allocated) 
    //and set the new one to nullptr
    m_context.reset();
  }

...

  /** CASTOR NsFileId file concerned */
  uint64_t m_fileid;

  /** number of the memory-chunk of the current file we are manipulating */
  uint64_t m_fileBlock;
  
  /** order of file on the tape */
  uint64_t m_fSeq;
  
  /** Sequence number of the first tape block file in this memory block */
  size_t m_tapeFileBlock;
  
  /** Size of the tape blocks, allowing sanity checks on the disk write side in recalls */
  size_t m_tapeBlockSize;