sd_bus_message_set_expect_reply - Man Page
Set and query bus message metadata
Synopsis
#include <systemd/sd-bus.h>
int sd_bus_message_set_expect_reply(sd_bus_message *message, int b);
int sd_bus_message_get_expect_reply(sd_bus_message *message);
int sd_bus_message_set_auto_start(sd_bus_message *message, int b);
int sd_bus_message_get_auto_start(sd_bus_message *message);
int sd_bus_message_set_allow_interactive_authorization(sd_bus_message *message, int b);
int sd_bus_message_get_allow_interactive_authorization(sd_bus_message *message);
Description
sd_bus_message_set_expect_reply() sets or clears the NO_REPLY_EXPECTED flag on the message m. This flag matters only for method call messages and is used to specify that no method return or error reply is expected. It is ignored for other types. Thus, for a method call message, calling
sd_bus_message_set_expect_reply(..., 0)
sets the flag and suppresses the reply.
sd_bus_message_get_expect_reply() checks if the NO_REPLY_EXPECTED flag is set on the message m. It will return positive if it is not set, and zero if it is.
sd_bus_message_set_auto_start() sets or clears the NO_AUTO_START flag on the message m. When the flag is set, the bus must not launch an owner for the destination name in response to this message. Calling
sd_bus_message_set_auto_start(..., 0)
sets the flag.
sd_bus_message_get_auto_start() checks if the NO_AUTO_START flag is set on the message m. It will return positive if it is not set, and zero if it is.
sd_bus_message_set_allow_interactive_authorization() sets or clears the ALLOW_INTERACTIVE_AUTHORIZATION flag on the message m. Setting this flag informs the receiver that the caller is prepared to wait for interactive authorization via polkit or a similar framework. Note that setting this flag does not guarantee that the receiver will actually perform interactive authorization. Also, make sure to set a suitable message timeout when using this flag since interactive authorization could potentially take a long time as it depends on user input. If b is non-zero, the flag is set.
sd_bus_message_get_allow_interactive_authorization() checks if the ALLOW_INTERACTIVE_AUTHORIZATION flag is set on the message m. It will return a positive integer if the flag is set. Otherwise, it returns zero.
Return Value
On success, these functions return a non-negative integer. On failure, they return a negative errno-style error code.
Errors
Returned errors may indicate the following problems:
- -EINVAL
The message parameter is NULL.
- -EPERM
The message message is sealed when trying to set a flag.
The message message has wrong type.
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.
All functions listed here are thread-agnostic and only a single thread may operate on a given object at any given time. Different threads may access the same object at different times. Multiple independent objects may be used from different threads in parallel.
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.
History
sd_bus_message_set_expect_reply(), sd_bus_message_get_expect_reply(), sd_bus_message_set_auto_start(), and sd_bus_message_get_auto_start() were added in version 240.
sd_bus_message_set_allow_interactive_authorization() and sd_bus_message_get_allow_interactive_authorization() were added in version 246.