#include <systemd/sd-bus.h>
sd_bus_enqueue_for_read()
This call is primarily useful for dealing with incoming method calls that may be processed only after an additional asynchronous operation completes. One example are PolicyKit authorization requests that are determined to be necessary to authorize a newly incoming method call: when the PolicyKit response is received the original method call may be re-enqueued to process it again, this time with the authorization result known.
On success, this function return 0 or a positive integer. On failure, it returns a negative errno-style error code.
Returned errors may indicate the following problems:
-ECHILD
These APIs are implemented as a shared library, which can be compiled and linked to with the libsystemd pkg-config(1) file.
systemd(1), sd-bus(3), sd_bus_send(3),