x SuSE Linux 13.1-RELEASE x
x SuSE Linux 13.1-RELEASEx
SD_BUS_MESSAGE_GET_COOKIE(3sd_bus_message_get_cookSD_BUS_MESSAGE_GET_COOKIE(3)
NAME
sd_bus_message_get_cookie, sd_bus_message_get_reply_cookie - Returns
the transaction cookie of a message
SYNOPSIS
#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
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.
RETURN VALUE
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.
NOTES
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.
SEE ALSO
systemd(1), sd-bus(3), sd_bus_new(3)
systemd 254 SD_BUS_MESSAGE_GET_COOKIE(3)
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