# sd_bus_close

## 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.
    


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