NAME¶

sd_bus_set_property, sd_bus_set_propertyv, sd_bus_get_property, sd_bus_get_property_trivial, sd_bus_get_property_string, sd_bus_get_property_strv - Set or query D-Bus service properties

SYNOPSIS¶

#include <systemd/sd-bus.h>

int sd_bus_set_property(sd_bus *bus, const char *destination, const char *path, const char *interface, const char *member, sd_bus_error *ret_error, sd_bus_message **reply, const char *type, ...);

int sd_bus_set_propertyv(sd_bus *bus, const char *destination, const char *path, const char *interface, const char *member, sd_bus_error *ret_error, sd_bus_message **reply, const char *type, va_list ap);

int sd_bus_get_property(sd_bus *bus, const char *destination, const char *path, const char *interface, const char *member, sd_bus_error *ret_error, sd_bus_message **reply, const char *type);

int sd_bus_get_property_trivial(sd_bus *bus, const char *destination, const char *path, const char *interface, const char *member, sd_bus_error *ret_error, char type, void *ret_ptr);

int sd_bus_get_property_string(sd_bus *bus, const char *destination, const char *path, const char *interface, const char *member, sd_bus_error *ret_error, char **ret);

int sd_bus_get_property_strv(sd_bus *bus, const char *destination, const char *path, const char *interface, const char *member, sd_bus_error *ret_error, char ***ret);

DESCRIPTION¶

These functions set or query D-Bus properties. D-Bus properties are service fields exposed via the org.freedesktop.DBus.Properties interface. Under the hood, these functions call methods of the org.freedesktop.DBus.Properties interface and as a result their semantics are similar to sd_bus_call_method(3).

sd_bus_set_property() sets a D-Bus property. On success, the response is stored in reply. If setting the property fails or an internal error occurs, an error is returned and an extended description of the error is optionally stored in ret_error if it is not NULL. type and the arguments that follow it describe the new value of the property and must follow the format described in sd_bus_message_append(3).

sd_bus_set_propertyv() is equivalent to sd_bus_set_property(), except that it is called with a "va_list" instead of a variable number of arguments.

sd_bus_get_property() queries a D-Bus property. If retrieving the property fails or an internal error occurs, an error is returned and an extended description of the error is optionally stored in ret_error if it is not NULL. On success, the property is stored in reply. type describes the property type and must follow the format described in sd_bus_message_append(3).

sd_bus_get_property_trivial(), sd_bus_get_property_string() and sd_bus_get_property_strv() are shorthands for sd_bus_get_property() that are used to query basic, string and string vector properties respectively. The caller is responsible for freeing the string and string vector results stored in ret by sd_bus_get_property_string() and sd_bus_get_property_strv().

RETURN VALUE¶

On success, these functions return a non-negative integer. On failure, they return a negative errno-style error code.

NOTES¶

These APIs are implemented as a shared library, which can be compiled and linked to with the libsystemd pkg-config(1) file.

SEE ALSO¶

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