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NAME |SYNOPSIS |DESCRIPTION |RETURN VALUE |NOTES |HISTORY |SEE ALSO |COLOPHON | |
SD_BUS_M...ET_COOKIE(3) sd_bus_message_get_cookieSD_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 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_message_get_cookie()andsd_bus_message_get_reply_cookie() were added in version 209.
systemd(1),sd-bus(3),sd_bus_new(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_M...ET_COOKIE(3)Pages that refer to this page:sd-bus(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. | |