sd_bus_close - Man Page

#include <systemd/sd-bus​.h>

void sd_bus_close(sd_bus *bus);

int sd_bus_flush(sd_bus *bus);

void sd_bus_default_flush_close(void);

sd_bus_close() disconnects the specified bus connection​. When this call is invoked and the specified bus object refers to an active connection it is immediately terminated​. No further messages may be sent or received on it​. Any messages queued in the bus object (both incoming and outgoing) are released​. If invoked on NULL bus object or when the bus connection is already closed this function executes no operation​. This call does not free or unreference the bus object itself​. Use sd_bus_unref(3) for that​.

sd_bus_flush() synchronously writes out all outgoing queued message on a bus connection if there are any​. This function call may block if the peer is not processing bus messages quickly​.

Before a program exits it is usually a good idea to flush any pending messages with sd_bus_flush() and then close connections with sd_bus_close() to ensure that no unwritten messages are lost, no further messages may be queued and all incoming but unprocessed messages are released​. After both operations have been done, it is a good idea to also drop any remaining references to the bus object so that it may be freed​. Since these three operations are frequently done together a helper call sd_bus_flush_close_unref(3) is provided that combines them into one​.

sd_bus_default_flush_close() is similar to sd_bus_flush_close_unref(), but does not take a bus pointer argument and instead iterates over any of the "default" buses opened by sd_bus_default(3), sd_bus_default_user(3), sd_bus_default_system(3), and similar calls​. sd_bus_default_flush_close() is particularly useful to clean up any buses opened using those calls before the program exits​.

On success, sd_bus_flush() returns a non-negative integer​. On failure, it returns a negative errno-style error code​.

Functions described here are available as a shared library, which can be compiled against and linked to with the libsystemd ​pkg-config(1) file​.

All functions listed here are thread-agnostic and only a single thread may operate on a given object at any given time​. Different threads may access the same object at different times​. Multiple independent objects may be used from different threads in parallel​.

The code described here uses getenv(3), which is declared to be not multi-thread-safe​. This means that the code calling the functions described here must not call setenv(3) from a parallel thread​. It is recommended to only do calls to setenv() from an early phase of the program when no other threads have been started​.

sd_bus_close() and sd_bus_flush() were added in version 221​.

sd_bus_default_flush_close() was added in version 227​.

systemd(1), sd-bus(3), sd_bus_unref(3), sd_bus_set_close_on_exit(3)