| SD_BUS_CLOSE(3) | sd_bus_close | SD_BUS_CLOSE(3) |
.SH "NAME" sd_bus_close, sd_bus_flush, sd_bus_default_flush_close -
Close and flush a bus connection
.SH "SYNOPSIS"
#include <systemd/sd-bus.h>
.HP 432u void sd_bus_close(sd_bus *bus);
.HP 408u int sd_bus_flush(sd_bus *bus);
.HP 768u void sd_bus_default_flush_close(void);
.SH "DESCRIPTION"
.PP 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.
.PP 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.
.PP 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.
.PP 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.
.SH "RETURN VALUE"
.PP On success, sd_bus_flush() returns a non-negative integer. On
failure, it returns a negative errno-style error code.
.SS "Errors"
.PP Returned errors may indicate the following problems:
.PP -ECHILD
The bus connection has been created in a different process, library or module
instance.
.RE
.SH "NOTES"
.PP Functions described here are available as a shared library, which can be
compiled against and linked to with the
libsystemd pkg-config(1) file.
.PP 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.
.PP 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.
.SH "HISTORY"
.PP sd_bus_close() and sd_bus_flush() were added in version
221.
.PP sd_bus_default_flush_close() was added in version 227.
.SH "SEE ALSO"
.PP systemd(1), sd-bus(3), sd_bus_unref(3),
sd_bus_set_close_on_exit(3)
| systemd 262.2 |