sd_bus_wait(3) — Linux manual page


SD_BUS_WAIT(3)                   sd_bus_wait                  SD_BUS_WAIT(3)

NAME         top

       sd_bus_wait - Wait for I/O on a bus connection

SYNOPSIS         top

       #include <systemd/sd-bus.h>

       int sd_bus_wait(sd_bus *bus, uint64_t timeout_usec);

DESCRIPTION         top

       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(3), to wait for
       I/O on the bus connection. If the timeout_sec parameter is specified,
       the call will block at most for the specified amount of time in µs.
       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         top

       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.

       Returned errors may indicate the following problems:

           An invalid bus object was passed.

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

           The bus connection has been terminated already.

NOTES         top

       These APIs are implemented as a shared library, which can be compiled
       and linked to with the libsystemd pkg-config(1) file.

SEE ALSO         top

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

COLOPHON         top

       This page is part of the systemd (systemd system and service manager)
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       report for this manual page, see
       ⟨⟩.  This
       page was obtained from the project's upstream Git repository
       ⟨⟩ on 2020-09-18.  (At that
       time, the date of the most recent commit that was found in the repos‐
       itory was 2020-09-18.)  If you discover any rendering problems in
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       of the original manual page), send a mail to

systemd 246                                                   SD_BUS_WAIT(3)

Pages that refer to this page: sd_bus_attach_event(3)sd_bus_detach_event(3)sd_bus_get_event(3)sd_bus_get_events(3)sd_bus_get_fd(3)sd_bus_get_timeout(3)sd_bus_process(3)sd_bus_set_fd(3)30-systemd-environment-d-generator(7)systemd.directives(7)systemd.index(7)