AMQPQueue::nack

Mark a message as explicitly not acknowledged.

&reftitle.description; public `void` `AMQPQueue::nack` `string` `delivery_tag` `string` `flags` `AMQP_NOPARAM`

Mark the message identified by `delivery_tag` as explicitly not acknowledged. This method can only be called on messages that have not yet been acknowledged, meaning that messages retrieved with by `AMQPQueue::consume` and `AMQPQueue::get` and using the `AMQP_AUTOACK` flag are not eligible.

When called, the broker will immediately put the message back onto the queue, instead of waiting until the connection is closed.

This method is only supported by the RabbitMQ broker. The behavior of calling this method while connected to any other broker is undefined.

&reftitle.parameters;

`delivery_tag`

- The delivery tag by which to identify the message.

`flags`

- A bitmask of flags.

&reftitle.errors;

Throws `AMQPChannelException` if the channel is not open.

Throws `AMQPConnectionException` if the connection to the broker was lost.

&reftitle.returnvalues;

&return.success;