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(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 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

       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

HISTORY         top

       sd_bus_wait() was added in version 240.

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

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       This page was obtained from the project's upstream Git repository
       ⟨⟩ on 2023-12-22.  (At that
       time, the date of the most recent commit that was found in the
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       (which is not part of the original manual page), send a mail to

systemd 255                                               SD_BUS_WAIT(3)

Pages that refer to this page: sd_bus_attach_event(3)sd_bus_get_fd(3)sd_bus_process(3)systemd.directives(7)systemd.index(7)