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SD_BUS_MESSAGE_NEW_SIGNAL(3) sd_bus_message_new_signal SD_BUS_MESSAGE_NEW_SIGNAL(3)

NAME

sd_bus_message_new_signal, sd_bus_message_new_signal_to - Create a signal message

SYNOPSIS

#include <elogind/sd-bus.h>

int sd_bus_message_new_signal(sd_bus *bus, sd_bus_message **m, const char *path, const char *interface, const char *member);

int sd_bus_message_new_signal_to(sd_bus *bus, sd_bus_message **m, const char *destination, const char *path, const char *interface, const char *member);

DESCRIPTION

The sd_bus_message_new_signal() function creates a new bus message object that encapsulates a D-Bus signal, and returns it in the m output parameter. The signal will be sent to path path, on the interface interface, member member. When this message is sent, no reply is expected. See sd_bus_message_new_method_call(1) for a short description of the meaning of the path, interface, and member parameters.

sd_bus_message_new_signal_to() is a shorthand for creating a new bus message to a specific destination. It's behavior is similar to calling sd_bus_message_new_signal() followed by calling sd_bus_message_set_destination(3).

RETURN VALUE

This function returns 0 if the message object was successfully created, and a negative errno-style error code otherwise.

Errors

Returned errors may indicate the following problems:

-EINVAL

The output parameter m is NULL.

The path parameter is not a valid D-Bus path ("/an/object/path"), the interface parameter is not a valid D-Bus interface name ("an.interface.name"), or the member parameter is not a valid D-Bus member ("Name").

-ENOTCONN

The bus parameter bus is NULL or the bus is not connected.

-ENOMEM

Memory allocation failed.

NOTES

Functions described here are available as a shared library, which can be compiled against and linked to with the libelogind pkg-config(8) file.

SEE ALSO

elogind(8), sd-bus(3), sd_bus_emit_signal(3) sd_bus_message_set_destination(3)

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