# sd_event_source_set_floating

## NAME



           sd_event_source_set_floating, sd_event_source_get_floating - Set
           or retrieve 'floating' state of event sources
    


## SYNOPSIS



           **#include <systemd/sd-event.h>**
    
           **int sd_event_source_set_floating(sd_event_source ***_source_**,**
                                            **int** _floating_**);**
    
           **int sd_event_source_get_floating(sd_event_source ***_source_**);**
    


## DESCRIPTION



           **sd_event_source_set_floating()** takes a boolean and sets the
           'floating' state of the specified event source object. This is
           used to change the direction of reference counts for the object
           and the event loop it is associated with. In non-floating mode,
           the event source object holds a reference to the event loop
           object, but not vice versa. The creator of the event source object
           must hold a reference to it as long as the source should exist. In
           floating mode, the event loop holds a reference to the source
           object, and will decrease the reference count when being freed.
           This means that a reference to the event loop should be held to
           prevent both from being destroyed.
    
           Various calls that allocate event source objects (i.e.
           sd_event_add_io(3), sd_event_add_time(3) and similar) will
           automatically set an event source object to 'floating' mode if the
           caller passed **NULL** in the parameter used to return a reference to
           the event source object. Nevertheless, it may be necessary to gain
           temporary access to the source object, for example to adjust event
           source properties after allocation (e.g. its priority or
           description string). In those cases the object may be created in
           non-floating mode, and the returned reference used to adjust the
           properties, and the object marked as floating afterwards, and the
           reference in the caller dropped.
    
           **sd_event_source_get_floating()** may be used to query the current
           'floating' state of the event source object _source_. It returns
           zero if 'floating' mode is off, positive if it is on.
    


## RETURN VALUE



           On success, **sd_event_source_set_floating()** and
           **sd_event_source_get_floating()** return a non-negative integer. On
           failure, they return a negative errno-style error code.
    
       **Errors**
           Returned errors may indicate the following problems:
    
           **-EINVAL**
               _source_ is not a valid pointer to an sd_event_source object.
    
               Added in version 244.
    
           **-ECHILD**
               The event loop has been created in a different process,
               library or module instance.
    
               Added in version 244.
    


## 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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