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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | NOTES | 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(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).
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.
These APIs are implemented as a shared library, which can be compiled
and linked to with the libsystemd pkg-config(1) file.
systemd(1), sd-bus(3), sd_bus_process(3), sd_bus_get_fd(3),
sd-event(3), sd_bus_attach_event(3)
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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 2020-09-18. (At that
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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)
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