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Set powered state of the Adapter and Look for PropertiesChanged signal
/*
* bluez_adapter_set_properties.c - Set the Powered property of Adapter
* - The example uses GDBUS to set the Adapter Powered state to "on" and "off"
* in sequence.
* - It also registers signal handling for the PropertiesChanged event and prints
* the current powere state of the Adapter
* gcc `pkg-config --cflags glib-2.0 gio-2.0` -Wall -Wextra -o ./bin/bluez_adapter_set_properties ./bluez_adapter_set_properties.c `pkg-config --libs glib-2.0 gio-2.0`
*/
#include <glib.h>
#include <gio/gio.h>
GDBusConnection *con;
static void bluez_signal_adapter_changed(GDBusConnection *conn,
const gchar *sender,
const gchar *path,
const gchar *interface,
const gchar *signal,
GVariant *params,
void *userdata)
{
(void)conn;
(void)sender;
(void)path;
(void)interface;
static int exit = 0;
GVariantIter *properties = NULL;
GVariantIter *unknown = NULL;
const char *iface;
const char *key;
GVariant *value = NULL;
const gchar *signature = g_variant_get_type_string(params);
if(strcmp(signature, "(sa{sv}as)") != 0) {
g_print("Invalid signature for %s: %s != %s", signal, signature, "(sa{sv}as)");
goto done;
}
g_variant_get(params, "(&sa{sv}as)", &iface, &properties, &unknown);
while(g_variant_iter_next(properties, "{&sv}", &key, &value)) {
if(!g_strcmp0(key, "Powered")) {
if(!g_variant_is_of_type(value, G_VARIANT_TYPE_BOOLEAN)) {
g_print("Invalid argument type for %s: %s != %s", key,
g_variant_get_type_string(value), "b");
goto done;
}
g_print("Adapter is Powered \"%s\"\n", g_variant_get_boolean(value) ? "on" : "off");
exit++;
}
}
done:
if(properties != NULL)
g_variant_iter_free(properties);
if(value != NULL)
g_variant_unref(value);
if(exit == 2)
g_main_loop_quit((GMainLoop *)userdata);
}
static int bluez_adapter_set_property(const char *prop, GVariant *value)
{
GVariant *result;
GError *error = NULL;
result = g_dbus_connection_call_sync(con,
"org.bluez",
"/org/bluez/hci0",
"org.freedesktop.DBus.Properties",
"Set",
g_variant_new("(ssv)", "org.bluez.Adapter1", prop, value),
NULL,
G_DBUS_CALL_FLAGS_NONE,
-1,
NULL,
&error);
if(error != NULL)
return 1;
g_variant_unref(result);
return 0;
}
int main(void)
{
GMainLoop *loop;
int rc;
guint sub;
con = g_bus_get_sync(G_BUS_TYPE_SYSTEM, NULL, NULL);
if(con == NULL) {
g_print("Not able to get connection to system bus\n");
return 1;
}
loop = g_main_loop_new(NULL, FALSE);
sub = g_dbus_connection_signal_subscribe(con,
"org.bluez",
"org.freedesktop.DBus.Properties",
"PropertiesChanged",
NULL,
"org.bluez.Adapter1",
G_DBUS_SIGNAL_FLAGS_NONE,
bluez_signal_adapter_changed,
loop,
NULL);
rc = bluez_adapter_set_property("Powered", g_variant_new("b", TRUE));
if(rc) {
g_print("Not able to enable the adapter\n");
g_main_loop_quit(loop);
}
rc = bluez_adapter_set_property("Powered", g_variant_new("b", FALSE));
if(rc) {
g_print("Not able to disable the adapter\n");
g_main_loop_quit(loop);
}
g_main_loop_run(loop);
g_dbus_connection_signal_unsubscribe(con, sub);
g_object_unref(con);
return 0;
}
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