Method

GioDatagramBasedcondition_check

Declaration

GIOCondition
g_datagram_based_condition_check (
  GDatagramBased* datagram_based,
  GIOCondition condition
)

Description

Checks on the readiness of datagram_based to perform operations. The operations specified in condition are checked for and masked against the currently-satisfied conditions on datagram_based. The result is returned.

G_IO_IN will be set in the return value if data is available to read with g_datagram_based_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 g_socket_close() or g_socket_shutdown() with shutdown_read set, if it’s a GSocket).

If the connection is shut down or closed (by calling g_socket_close() or g_socket_shutdown() with shutdown_read set, if it’s a GSocket, for example), all calls to this function will return G_IO_ERROR_CLOSED.

G_IO_OUT will be set if it is expected that at least one byte can be sent using g_datagram_based_send_messages() without blocking. It will not be set if the datagram_based has been closed locally.

G_IO_HUP will be set if the connection has been closed locally.

G_IO_ERR will be set if there was an asynchronous error in transmitting data previously enqueued using g_datagram_based_send_messages().

Note that on Windows, it is possible for an operation to return G_IO_ERROR_WOULD_BLOCK even immediately after g_datagram_based_condition_check() has claimed that the GDatagramBased is ready for writing. Rather than calling g_datagram_based_condition_check() and then writing to the GDatagramBased if it succeeds, it is generally better to simply try writing right away, and try again later if the initial attempt returns G_IO_ERROR_WOULD_BLOCK.

It is meaningless to specify G_IO_ERR or G_IO_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.

Available since:2.48

Parameters

condition

Type: GIOCondition

A GIOCondition mask to check.

Return value

Type: GIOCondition

The GIOCondition mask of the current state.