diff --git a/mlib.html b/mlib.html
index e8f5dac3..64a79a99 100644
--- a/mlib.html
+++ b/mlib.html
@@ -1431,7 +1431,7 @@
     ab"
 
 ### Function: error
-    (error [condition-type] control-string args*) -> |
+    (error [condition-type] controlstring-or-formatfunction args*) -> |
 
 Since: 1.5
 
diff --git a/mlib.md b/mlib.md
index 165d1a99..7388b7bd 100644
--- a/mlib.md
+++ b/mlib.md
@@ -1422,7 +1422,7 @@ Sample usage:
     ab"
 
 ### Function: error
-    (error [condition-type] control-string args*) -> |
+    (error [condition-type] controlstring-or-formatfunction args*) -> |
 
 Since: 1.5
 
diff --git a/samples.murmel-mlib/mlib.lisp b/samples.murmel-mlib/mlib.lisp
index 21a08930..7891e76d 100644
--- a/samples.murmel-mlib/mlib.lisp
+++ b/samples.murmel-mlib/mlib.lisp
@@ -4222,13 +4222,13 @@
 
 
 ;;; = Function: error
-;;;     (error [condition-type] control-string args*) -> |
+;;;     (error [condition-type] controlstring-or-formatfunction args*) -> |
 ;;;
 ;;; Since: 1.5
 ;;;
 ;;; A simplified subset of Common Lisp's function `error`.
 (defun error (datum . args)
-  (if (typep datum 'symbol)
+  (if (symbolp datum)
       (jerror datum (apply format (cons nil args)))
       (jerror 'simple-error (apply format (list* nil datum args)))))