[ace-users] ACE_FILE_LOCK using handle owned by ACE_FILE_LOCK

Gudugunta, Sukumar Sukumar.Gudugunta at philips.com
Tue Feb 2 13:58:30 CST 2016

Hi All

We are using ACE_FILE_LOCK object to lock the file (read/write). Here am using   set handle (ACE_HANDLE) method to set the handle for the lock.
Can anyone let me know why we need to set this handle?

Once we acquire the lock can I use the same handle to truncate and rewrite the whole file? Does it cause any dead locks?

int err= 0;
  err = ACE_OS::ftruncate(m_lock.get_handle(),0);
  //Here we have opened the two handles(Open method) above. using m_handle we can't overwrite first byts of the file
  //Since the iFileLocK mechanism locks the first byte of the file.hence using the handle owned by m_lock to overwrite the entire file
  ACE_UINT64 qwPosition = 0;
  if(!Stentor::FileSeek(m_lock.get_handle(),offset,FILE_BEGIN, qwPosition))
    throw OSError("FileSeek failed",m_path.c_str(),THISFILE,__LINE__);

  throw OSError("Write failed",m_path.c_str(),THISFILE,__LINE__);

As per my understanding ACE_FILE_LOCK locks the offset of first byte in the file. Please let me know if this is correct?
Thanks in advance


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