NAME         top

       sd_bus_message_get_cookie, sd_bus_message_get_reply_cookie - Returns
       the transaction cookie of a message

SYNOPSIS         top

       #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);

DESCRIPTION         top

       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

       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.

RETURN VALUE         top

       On success, these calls return 0 or a positive integer. On failure,
       these calls return a negative errno-style error code.

       On success, the cookie/reply cookie is returned in the specified
       64-bit unsigned integer variable.

ERRORS         top

       Returned errors may indicate the following problems:

           A specified parameter is invalid.

           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.

NOTES         top

       The sd_bus_message_get_cookie() and sd_bus_message_get_reply_cookie()
       interfaces are available as a shared library, which can be compiled
       and linked to with the libsystemd pkg-config(1) file.

SEE ALSO         top

       systemd(1), sd-bus(3), sd_bus_new(3)

COLOPHON         top

       This page is part of the systemd (systemd system and service manager)
       project.  Information about the project can be found at 
       ⟨⟩.  If you have a bug
       report for this manual page, see 
       ⟨⟩.  This
       page was obtained from the project's upstream Git repository 
       ⟨⟩ on 2017-03-13.  If you dis‐
       cover any rendering problems in this HTML version of the page, or you
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       you have corrections or improvements to the information in this
       COLOPHON (which is not part of the original manual page), send a mail

systemd 233                                     SD_BUS_MESSAGE_GET_COOKIE(3)