diff --git a/src/or/buffers.c b/src/or/buffers.c
index d60e54e87a..aa3e01fd9d 100644
--- a/src/or/buffers.c
+++ b/src/or/buffers.c
@@ -1011,7 +1011,7 @@ fetch_from_buf(char *string, size_t string_len, buf_t *buf)
 
 /** True iff the cell command <b>command</b> is one that implies a
  * variable-length cell in Tor link protocol <b>linkproto</b>. */
-static inline int
+static INLINE int
 cell_command_is_var_length(uint8_t command, int linkproto)
 {
   /* If linkproto is v2 (2), CELL_VERSIONS is the only variable-length cells