diff --git a/include/tinyalsa/pcm.h b/include/tinyalsa/pcm.h
index f32e11d..a49746c 100644
--- a/include/tinyalsa/pcm.h
+++ b/include/tinyalsa/pcm.h
@@ -341,6 +341,8 @@ int pcm_mmap_begin(struct pcm *pcm, void **areas, unsigned int *offset, unsigned
 
 int pcm_mmap_commit(struct pcm *pcm, unsigned int offset, unsigned int frames);
 
+int pcm_mmap_avail(struct pcm *pcm);
+
 int pcm_link(struct pcm *pcm1, struct pcm *pcm2);
 
 int pcm_unlink(struct pcm *pcm);
diff --git a/src/pcm.c b/src/pcm.c
index 8da3241..e88c18c 100644
--- a/src/pcm.c
+++ b/src/pcm.c
@@ -1236,7 +1236,7 @@ static inline int pcm_mmap_capture_avail(struct pcm *pcm)
     return avail;
 }
 
-static inline int pcm_mmap_avail(struct pcm *pcm)
+int pcm_mmap_avail(struct pcm *pcm)
 {
     if (pcm->flags & PCM_IN)
         return pcm_mmap_capture_avail(pcm);