sd_bus_get_n_queued_read, sd_bus_get_n_queued_write — Get the number of pending bus messages in the read and write queues of a bus connection object
#include <systemd/sd-bus.h>
int sd_bus_get_n_queued_read( | sd_bus *bus, |
uint64_t *ret); |
int sd_bus_get_n_queued_write( | sd_bus *bus, |
uint64_t *ret); |
sd_bus_get_n_queued_read() may be used to query the number of bus messages in the read queue
of a bus connection object. The read queue contains all messages read from the transport medium (e.g. network
socket) but not yet processed locally. The function expects two arguments: the bus object to query, and a pointer
to a 64bit counter variable to write the current queue size to. Use sd_bus_process() in
order to process queued messages, i.e. to reduce the size of the read queue (as well as, in fact, the write
queue, see below).
Similarly, sd_bus_get_n_queued_write() may be used to query the number of currently pending
bus messages in the write queue of a bus connection object. The write queue contains all messages enqueued into
the connection with a call such as sd_bus_send() but not yet written to the transport
medium. The expected arguments are similar to sd_bus_get_n_queued_read(). Here too, use
sd_bus_process() to reduce the size of the write queue. Alternatively, use
sd_bus_flush() to synchronously write out any pending bus messages until the write queue is
empty.
On success, these functions return 0 or a positive integer. On failure, they return a negative errno-style error code.