SD_BUS_WAIT(3)                    sd_bus_wait                   SD_BUS_WAIT(3)

NAME
       sd_bus_wait - Wait for I/O on a bus connection

SYNOPSIS
       #include <systemd/sd-bus.h>

       int sd_bus_wait(sd_bus *bus, uint64_t timeout_usec);

DESCRIPTION
       sd_bus_wait() synchronously waits for I/O on the specified bus
       connection object. This function is supposed to be called whenever
       sd_bus_process(3) returns zero, indicating that no work is pending on
       the connection. Internally, this call invokes ppoll(2), to wait for I/O
       on the bus connection. If the timeout_usec parameter is specified, the
       call will block at most for the specified amount of time in <mu>s. Pass
       UINT64_MAX to permit it to sleep indefinitely.

       After each invocation of sd_bus_wait() the sd_bus_process() call should
       be invoked in order to process any now pending I/O work.

       Note that sd_bus_wait() is suitable only for simple programs as it does
       not permit waiting for other I/O events. For more complex programs
       either connect the bus connection object to an external event loop
       using sd_bus_get_fd(3) or to an sd-event(3) event loop using
       sd_bus_attach_event(3).

RETURN VALUE
       If any I/O was seen, a positive value is returned, zero otherwise. If
       an error occurs, a negative errno-style error code is returned.

   Errors
       Returned errors may indicate the following problems:

       -EINVAL
           An invalid bus object was passed.

       -ECHILD
           The bus connection was allocated in a parent process and is being
           reused in a child process after fork().

       -ENOTCONN
           The bus connection has been terminated already.

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_wait() was added in version 240.

SEE ALSO
       systemd(1), sd-bus(3), sd_bus_process(3), sd_bus_get_fd(3), sd-
       event(3), sd_bus_attach_event(3)

systemd 255                                                     SD_BUS_WAIT(3)