libhal_device_exists
if (libhal_device_exists(ctx, udi, &error) == TRUE)
dev_exists = libhal_device_exists(hal_ctx, udi, &error);
udi_exists = libhal_device_exists (hal_ctx, udi, &error);
udi_exists = libhal_device_exists (hal_ctx, udi, &error);
if (!libhal_device_exists (hal_ctx, udi, &error)) {
dbus_bool_t libhal_device_exists (LibHalContext *ctx, const char *udi, DBusError *error);