Trait gio::prelude::DatagramBasedExt
source · pub trait DatagramBasedExt: 'static {
// Required method
fn condition_check(&self, condition: IOCondition) -> IOCondition;
}Expand description
Required Methods§
sourcefn condition_check(&self, condition: IOCondition) -> IOCondition
fn condition_check(&self, condition: IOCondition) -> IOCondition
Checks on the readiness of self to perform operations. The
operations specified in condition are checked for and masked against the
currently-satisfied conditions on self. The result is returned.
glib::IOCondition::IN will be set in the return value if data is available to read with
DatagramBasedExtManual::receive_messages(), or if the connection is closed remotely
(EOS); and if the datagram_based has not been closed locally using some
implementation-specific method (such as SocketExt::close() or
SocketExt::shutdown() with shutdown_read set, if it’s a Socket).
If the connection is shut down or closed (by calling SocketExt::close() or
SocketExt::shutdown() with shutdown_read set, if it’s a Socket, for
example), all calls to this function will return IOErrorEnum::Closed.
glib::IOCondition::OUT will be set if it is expected that at least one byte can be sent
using DatagramBasedExtManual::send_messages() without blocking. It will not be set
if the datagram_based has been closed locally.
glib::IOCondition::HUP will be set if the connection has been closed locally.
glib::IOCondition::ERR will be set if there was an asynchronous error in transmitting data
previously enqueued using DatagramBasedExtManual::send_messages().
Note that on Windows, it is possible for an operation to return
IOErrorEnum::WouldBlock even immediately after
condition_check() has claimed that the DatagramBased is
ready for writing. Rather than calling condition_check() and
then writing to the DatagramBased if it succeeds, it is generally better to
simply try writing right away, and try again later if the initial attempt
returns IOErrorEnum::WouldBlock.
It is meaningless to specify glib::IOCondition::ERR or glib::IOCondition::HUP in condition; these
conditions will always be set in the output if they are true. Apart from
these flags, the output is guaranteed to be masked by condition.
This call never blocks.
condition
a glib::IOCondition mask to check
Returns
the glib::IOCondition mask of the current state