File lock types.

• read_lock = LOCK_SH
• write_lock = LOCK_EX

File-based mutex.

• Uses the sanest (but not very portable) flock(2) system call for file locking.
• Read locks may be acquired by multiple processes, provided that there no write lock on the file.
• Write lock may be acquired by only one process.

Base classes

• public sys::fildes

Methods

• open(const char * filename, open_flag flags = open_flag(), mode_type mode = 0) -> void

  Init file descriptor by opening file filename with open flags flags and mode mode.

  bad_call

  
  

• open(const char * filename, mode_type mode) -> void

  Open file filename for mutex with read-write permissions and file mode mode.

• file_mutex(const char * filename, mode_type mode)

  Construct file mutex with file filename, read-write permissions, file mode mode.

• file_mutex(const char * filename, open_flag flags, mode_type mode)

  Construct file mutex with file filename, flags flags, file mode mode.

• file_mutex()
• try_lock(file_lock_type tp = file_lock_type::write_lock) -> bool

  Try to acquire file lock of type tp.

• unlock() -> void

  Release file lock.

• lock(file_lock_type tp = file_lock_type::write_lock) -> void

  Acquire file lock of type tp.