diff --git a/libavutil/audio_fifo.h b/libavutil/audio_fifo.h
index d93be2aeb0..24f91dab72 100644
--- a/libavutil/audio_fifo.h
+++ b/libavutil/audio_fifo.h
@@ -73,6 +73,7 @@ AVAudioFifo *av_audio_fifo_alloc(enum AVSampleFormat sample_fmt, int channels,
  * @param nb_samples  new allocation size, in samples
  * @return            0 if OK, or negative AVERROR code on failure
  */
+av_warn_unused_result
 int av_audio_fifo_realloc(AVAudioFifo *af, int nb_samples);
 
 /**