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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | NOTES | HISTORY | SEE ALSO | COLOPHON |
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SD_BUS_WAIT(3) sd_bus_wait SD_BUS_WAIT(3)
sd_bus_wait - Wait for I/O on a bus connection
#include <systemd/sd-bus.h>
int sd_bus_wait(sd_bus *bus, uint64_t timeout_usec);
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).
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.
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.
sd_bus_wait() was added in version 240.
systemd(1), sd-bus(3), sd_bus_process(3), sd_bus_get_fd(3),
sd-event(3), sd_bus_attach_event(3)
This page is part of the systemd (systemd system and service
manager) project. Information about the project can be found at
⟨http://www.freedesktop.org/wiki/Software/systemd⟩. If you have
a bug report for this manual page, see
⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩.
This page was obtained from the project's upstream Git repository
⟨https://github.com/systemd/systemd.git⟩ on 2023-12-22. (At that
time, the date of the most recent commit that was found in the
repository was 2023-12-22.) If you discover any rendering
problems in this HTML version of the page, or you believe there
is a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
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)
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HTML rendering created 2023-12-22 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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