diff --git a/lib_eio/unix/cap.c b/lib_eio/unix/cap.c
index 2c9d81ff0..cae6b6468 100644
--- a/lib_eio/unix/cap.c
+++ b/lib_eio/unix/cap.c
@@ -1,10 +1,13 @@
 #include "primitives.h"
 
-#define HAVE_CAP_ENTER
-
 #include <errno.h>
+#include <sys/param.h>
+
+#ifdef __FreeBSD__
+# define HAVE_CAPSICUM
+#endif
 
-#ifdef HAVE_CAP_ENTER
+#ifdef HAVE_CAPSICUM
 # include <sys/capsicum.h>
 #endif
 
@@ -12,13 +15,13 @@
 #include <caml/unixsupport.h>
 
 CAMLprim value eio_unix_cap_enter(value v_unit) {
-#ifdef HAVE_CAP_ENTER
+#ifdef HAVE_CAPSICUM
   int r = cap_enter();
   if (r == -1 && errno != ENOSYS)
     caml_uerror("cap_enter", Nothing);
 
-  return Val_bool(r == 0)
+  return Val_bool(r == 0);
 #else
-  return Val_bool(0)
+  return Val_bool(0);
 #endif
 }
diff --git a/lib_eio/unix/cap.ml b/lib_eio/unix/cap.ml
index 9244f8823..fbb7841f0 100644
--- a/lib_eio/unix/cap.ml
+++ b/lib_eio/unix/cap.ml
@@ -1,5 +1,5 @@
 external eio_cap_enter : unit -> bool = "eio_unix_cap_enter"
 
-let cap_enter () =
+let enter () =
   if eio_cap_enter () then Ok ()
   else Error `Not_supported
diff --git a/lib_eio/unix/cap.mli b/lib_eio/unix/cap.mli
index fb3d08e74..a4718ef98 100644
--- a/lib_eio/unix/cap.mli
+++ b/lib_eio/unix/cap.mli
@@ -1 +1 @@
-val cap_enter : unit -> (unit, [`Not_supported]) result
+val enter : unit -> (unit, [`Not_supported]) result