diff --git a/circ_buf.c b/circ_buf.c
index e0d7dac..895ad85 100644
--- a/circ_buf.c
+++ b/circ_buf.c
@@ -85,7 +85,7 @@ size_t circ_peak(struct circ_buf *circ, void *buf, size_t len)
 		tail = (tail + 1) & (CIRC_BUF_SIZE - 1);
 	}
 
-	return (void*)p - buf;
+	return p - (char *)buf;
 }
 
 size_t circ_read(struct circ_buf *circ, void *buf, size_t len)
@@ -101,5 +101,5 @@ size_t circ_read(struct circ_buf *circ, void *buf, size_t len)
 		circ->tail = (circ->tail + 1) & (CIRC_BUF_SIZE - 1);
 	}
 
-	return (void*)p - buf;
+	return p - (char *)buf;
 }