sd_bus_message_set

Name

sd_bus_message_set_destination, sd_bus_message_get_destination, sd_bus_message_get_path, sd_bus_message_get_interface, sd_bus_message_get_member, sd_bus_message_set_sender, sd_bus_message_get_sender — Set and query bus message addressing information

Synopsis

#include <systemd/sd-bus.h>

`int sd_bus_message_set_destination(`	sd_bus_message *`message`,
	const char *`destination)`;

const char* sd_bus_message_get_destination( sd_bus_message *message);

const char* sd_bus_message_get_path( sd_bus_message *message);

const char* sd_bus_message_get_interface( sd_bus_message *message);

const char* sd_bus_message_get_member( sd_bus_message *message);

`int sd_bus_message_set_sender(`	sd_bus_message *`message`,
	const char *`sender)`;

const char* sd_bus_message_get_sender( sd_bus_message *message);

Description¶

sd_bus_message_set_destination() sets the destination service name for the specified bus message object. The specified name must be a valid unique or well-known service name.

sd_bus_message_get_destination(), sd_bus_message_get_path(), sd_bus_message_get_interface(), and sd_bus_message_get_member() return the destination, path, interface, and member fields from message header. The return value will be NULL is message is NULL or the message is of a type that doesn't use those fields or the message doesn't have them set. See sd_bus_message_new_method_call(3) and sd_bus_message_set_destination(3) for more discussion of those values.

sd_bus_message_set_sender() sets the sender service name for the specified bus message object. The specified name must be a valid unique or well-known service name. This function is useful only for messages to send on direct connections as for connections to bus brokers the broker will fill in the destination field anyway, and the sender field set by original sender is ignored.

sd_bus_message_get_sender() returns the sender field from message.

When a string is returned, it is a pointer to internal storage, and may not be modified or freed. It is only valid as long as the message remains referenced and this field hasn't been changed by a different call.

Return Value¶

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

Errors¶

Returned errors may indicate the following problems:

-EINVAL¶: The message parameter or the output parameter are NULL.
-EPERM¶: For sd_bus_message_set_destination() and sd_bus_message_set_sender(), the message is already sealed.
-EEXIST¶: The message already has a destination or sender field set.

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.

History¶

sd_bus_message_set_destination() and sd_bus_message_set_sender() were added in version 237.

sd_bus_message_get_destination(), sd_bus_message_get_path(), sd_bus_message_get_interface(), sd_bus_message_get_member(), and sd_bus_message_get_sender() were added in version 240.