...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
Inherited from basic_file.
Cancel all asynchronous operations associated with the file.
void cancel( boost::system::error_code & ec);
This function causes all outstanding asynchronous read and write operations
to finish immediately, and the handlers for cancelled operations will
be passed the boost::asio::error::operation_aborted
error.
Set to indicate what error occurred, if any.
Calls to cancel()
will always fail with boost::asio::error::operation_not_supported
when run on Windows XP, Windows Server 2003, and earlier versions of
Windows, unless BOOST_ASIO_ENABLE_CANCELIO is defined. However, the CancelIo
function has two issues that should be considered before enabling its
use:
For portable cancellation, consider using the close()
function
to simultaneously cancel the outstanding operations and close the file.
When running on Windows Vista, Windows Server 2008, and later, the CancelIoEx function is always used. This function does not have the problems described above.