# sd_session_is_active

## NAME



           sd_session_is_active, sd_session_is_remote, sd_session_get_state,
           sd_session_get_uid, sd_session_get_username, sd_session_get_seat,
           sd_session_get_start_time, sd_session_get_service,
           sd_session_get_type, sd_session_get_class, sd_session_get_desktop,
           sd_session_get_display, sd_session_get_tty, sd_session_get_vt,
           sd_session_get_remote_host, sd_session_get_remote_user,
           sd_session_get_leader - Determine state of a specific session
    


## SYNOPSIS



           **#include <systemd/sd-login.h>**
    
           **int sd_session_is_active(const char ***_session_**);**
    
           **int sd_session_is_remote(const char ***_session_**);**
    
           **int sd_session_get_state(const char ***_session_**, char ****_state_**);**
    
           **int sd_session_get_uid(const char ***_session_**, uid_t ***_uid_**);**
    
           **int sd_session_get_username(const char ***_session_**, char ****_username_**);**
    
           **int sd_session_get_seat(const char ***_session_**, char ****_seat_**);**
    
           **int sd_session_get_start_time(const char ***_session_**,**
                                         **uint64_t ***_usec_**);**
    
           **int sd_session_get_service(const char ***_session_**, char ****_service_**);**
    
           **int sd_session_get_type(const char ***_session_**, char ****_type_**);**
    
           **int sd_session_get_class(const char ***_session_**, char ****_class_**);**
    
           **int sd_session_get_desktop(const char ***_session_**, char ****_desktop_**);**
    
           **int sd_session_get_display(const char ***_session_**, char ****_display_**);**
    
           **int sd_session_get_leader(const char ***_session_**, pid_t ***_leader_**);**
    
           **int sd_session_get_remote_host(const char ***_session_**,**
                                          **char ****_remote_host_**);**
    
           **int sd_session_get_remote_user(const char ***_session_**,**
                                          **char ****_remote_user_**);**
    
           **int sd_session_get_tty(const char ***_session_**, char ****_tty_**);**
    
           **int sd_session_get_vt(const char ***_session_**, unsigned int ***_vt_**);**
    


## DESCRIPTION



           **sd_session_is_active()** may be used to determine whether the
           session identified by the specified session identifier is
           currently active (i.e. currently in the foreground and available
           for user input) or not.
    
           **sd_session_is_remote()** may be used to determine whether the
           session identified by the specified session identifier is a remote
           session (i.e. its remote host is known) or not.
    
           **sd_session_get_state()** may be used to determine the state of the
           session identified by the specified session identifier. The
           following states are currently known: "online" (session logged in,
           but session not active, i.e. not in the foreground), "active"
           (session logged in and active, i.e. in the foreground), "closing"
           (session nominally logged out, but some processes belonging to it
           are still around). In the future additional states might be
           defined, client code should be written to be robust in regards to
           additional state strings being returned. This function is a more
           generic version of **sd_session_is_active()**. The returned string
           needs to be freed with the libc free(3) call after use.
    
           **sd_session_get_uid()** may be used to determine the user identifier
           of the Unix user the session identified by the specified session
           identifier belongs to.
    
           **sd_session_get_username()** may be used to determine the name of the
           Unix user the session identified by the specified session
           identifier belongs to. The returned string needs to be freed with
           the libc free(3) call after use.
    
           **sd_session_get_seat()** may be used to determine the seat identifier
           of the seat the session identified by the specified session
           identifier belongs to. Note that not all sessions are attached to
           a seat, this call will fail (returning **-ENODATA**) for them. The
           returned string needs to be freed with the libc free(3) call after
           use.
    
           **sd_session_get_start_time()** may be used to determine the start
           time of the session identified by the specified session identifier
           belongs to. The _usec_ is in microseconds since the epoch
           (**CLOCK_REALTIME**).
    
           **sd_session_get_service()** may be used to determine the name of the
           service (as passed during PAM session setup) that registered the
           session identified by the specified session identifier. The
           returned string needs to be freed with the libc free(3) call after
           use.
    
           **sd_session_get_type()** may be used to determine the type of the
           session identified by the specified session identifier. The
           returned string is one of "x11", "wayland", "tty", "mir" or
           "unspecified" and needs to be freed with the libc free(3) call
           after use.
    
           **sd_session_get_class()** may be used to determine the class of the
           session identified by the specified session identifier. The
           returned string is one of "user", "user-early", "user-light",
           "user-early-light", "user-incomplete", "greeter", "lock-screen",
           "background", "background-light", "manager" or "manager-early" and
           needs to be freed with the libc free(3) call after use.
    
           **sd_session_get_desktop()** may be used to determine the brand of the
           desktop running on the session identified by the specified session
           identifier. This field can be set freely by desktop environments
           and does not follow any special formatting. However, desktops are
           strongly recommended to use the same identifiers and
           capitalization as for _$XDG_CURRENT_DESKTOP_ , as defined by the
           **Desktop Entry Specification******[1]. The returned string needs to be
           freed with the libcfree(3) call after use.
    
           **sd_session_get_display()** may be used to determine the X11 display
           of the session identified by the specified session identifier. The
           returned string needs to be freed with the libc free(3) call after
           use.
    
           **sd_session_get_leader()** may be used to determine the PID of the
           leader of the session identified by the specified session
           identifier.
    
           **sd_session_get_remote_host()** may be used to determine the remote
           hostname of the session identified by the specified session
           identifier. The returned string needs to be freed with the libc
           free(3) call after use.
    
           **sd_session_get_remote_user()** may be used to determine the remote
           username of the session identified by the specified session
           identifier. The returned string needs to be freed with the libc
           free(3) call after use. Note that this value is rarely known to
           the system, and even then should not be relied on.
    
           **sd_session_get_tty()** may be used to determine the TTY device of
           the session identified by the specified session identifier. The
           returned string needs to be freed with the libc free(3) call after
           use.
    
           **sd_session_get_vt()** may be used to determine the VT number of the
           session identified by the specified session identifier. This
           function will return an error if the seat does not support VTs.
    
           If the _session_ parameter of any of these functions is passed as
           **NULL** , the operation is executed for the session the calling
           process is a member of, if there is any.
    


## RETURN VALUE



           If the test succeeds, **sd_session_is_active()** and
           **sd_session_is_remote()** return a positive integer; if it fails, 0.
           On success, **sd_session_get_state()** , **sd_session_get_uid()** ,
           **sd_session_get_username()** , **sd_session_get_seat()** ,
           **sd_session_get_service()** , **sd_session_get_type()** ,
           **sd_session_get_class()** , **sd_session_get_display()** ,
           **sd_session_get_leader()** , **sd_session_get_remote_user()** ,
           **sd_session_get_remote_host()** and **sd_session_get_tty()** return 0 or
           a positive integer. On failure, these calls return a negative
           errno-style error code.
    
       **Errors**
           Returned errors may indicate the following problems:
    
           **-ENXIO**
               The specified session does not exist.
    
           **-ENODATA**
               The given field is not specified for the described session.
    
           **-EINVAL**
               An input parameter was invalid (out of range, or **NULL** , where
               that is not accepted).
    
           **-ENOMEM**
               Memory allocation failed.
    


## 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.
    


## NOTES



            1. Desktop Entry Specification
               https://standards.freedesktop.org/desktop-entry-spec/latest/
    


* * *