diff --git a/libavdevice/internal.h b/libavdevice/internal.h
index 3cd1b0686e..e222cf204d 100644
--- a/libavdevice/internal.h
+++ b/libavdevice/internal.h
@@ -21,6 +21,7 @@
 
 #include "libavformat/avformat.h"
 
+av_warn_unused_result
 int ff_alloc_input_device_context(struct AVFormatContext **avctx, struct AVInputFormat *iformat,
                                   const char *format);