NAME

       sd_bus_close, sd_bus_flush, sd_bus_default_flush_close - Close and flush a bus connection

SYNOPSIS

       #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);

DESCRIPTION

       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.

RETURN VALUE

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

   Errors
       Returned errors may indicate the following problems:

       -ECHILD
           The bus connection has been created in a different process, library or module instance.

NOTES

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

       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.

HISTORY

       sd_bus_close() and sd_bus_flush() were added in version 240.

       sd_bus_default_flush_close() was added in version 246.

SEE ALSO

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