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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | NOTES | HISTORY | SEE ALSO | COLOPHON |
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SD_BUS_M...ET_COOKIE(3) sd_bus_message_get_cookie SD_BUS_M...ET_COOKIE(3)
sd_bus_message_get_cookie, sd_bus_message_get_reply_cookie -
Returns the transaction cookie of a message
#include <systemd/sd-bus.h>
int sd_bus_message_get_cookie(sd_bus_message *message,
uint64_t *cookie);
int sd_bus_message_get_reply_cookie(sd_bus_message *message,
uint64_t *cookie);
sd_bus_message_get_cookie() returns the transaction cookie of a
message. The cookie uniquely identifies a message within each bus
peer, but is not globally unique. It is assigned when a message is
sent.
sd_bus_message_get_reply_cookie() returns the transaction cookie
of the message the specified message is a response to. When a
reply message is generated for a method call message, its cookie
is copied over into this field. Note that while every message that
is transferred is identified by a cookie, only response messages
carry a reply cookie field.
Both functions take a message object as first parameter and a
place to store the 64-bit cookie in.
On success, these calls return 0 or a positive integer. On
failure, they return a negative errno-style error code.
On success, the cookie/reply cookie is returned in the specified
64-bit unsigned integer variable.
Errors
Returned errors may indicate the following problems:
-EINVAL
A specified parameter is invalid.
-ENODATA
No cookie has been assigned to this message. This either
indicates that the message has not been sent yet and hence has
no cookie assigned, or that the message is not a method
response message and hence carries a reply cookie field.
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_message_get_cookie() and sd_bus_message_get_reply_cookie()
were added in version 209.
systemd(1), sd-bus(3), sd_bus_new(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 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 is not part of the original manual page), send a mail to
man-pages@man7.org
systemd 258~rc2 SD_BUS_M...ET_COOKIE(3)
Pages that refer to this page: sd-bus(3), systemd.directives(7), systemd.index(7)
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HTML rendering created 2025-09-06 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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