Boost C++ Libraries

...one of the most highly regarded and expertly designed C++ library projects in the world. — Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

Construct and open a basic_file.

basic_file(
    const executor_type & ex,
    const std::string & path,
    file_base::flags open_flags);

This constructor initialises a file and opens it.

ex: The I/O executor that the file will use, by default, to dispatch handlers for any asynchronous operations performed on the file.
path: The path name identifying the file to be opened.
open_flags: A set of flags that determine how the file should be opened.