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NAME |SYNOPSIS |DESCRIPTION |RETURN VALUE |NOTES |HISTORY |SEE ALSO |COLOPHON | |
SD_BUS_WAIT(3) sd_bus_waitSD_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_ttimeout_usec);
sd_bus_wait()synchronously waits for I/O on the specified bus connection object. This function is supposed to be called wheneversd_bus_process(3) returns zero, indicating that no work is pending on the connection. Internally, this call invokesppoll(2), to wait for I/O on the bus connection. If thetimeout_usec parameter is specified, the call will block at most for the specified amount of time in μs. PassUINT64_MAXto permit it to sleep indefinitely. After each invocation ofsd_bus_wait()thesd_bus_process()call should be invoked in order to process any now pending I/O work. Note thatsd_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 usingsd_bus_get_fd(3) or to ansd-event(3) event loop usingsd_bus_attach_event(3).
If any I/O was seen, a positive value is returned, zero otherwise. If an error occurs, a negativeerrno-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 afterfork().-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 thelibsystemd pkg-config(1) file. The code described here usesgetenv(3), which is declared to be not multi-thread-safe. This means that the code calling the functions described here must not callsetenv(3) from a parallel thread. It is recommended to only do calls tosetenv()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 thesystemd (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 2025-08-11. (At that time, the date of the most recent commit that was found in the repository was 2025-08-11.) 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 isnot part of the original manual page), send a mail to man-pages@man7.orgsystemd 258~rc2SD_BUS_WAIT(3)Pages that refer to this page:sd-bus(3), sd_bus_attach_event(3), sd_bus_get_fd(3), sd_bus_process(3), systemd.directives(7), systemd.index(7)
HTML rendering created 2025-09-06 byMichael Kerrisk, author ofThe Linux Programming Interface. For details of in-depthLinux/UNIX system programming training courses that I teach, lookhere. Hosting byjambit GmbH. | |