--- Libc/Libc-262/string/strspn.3
+++ Libc/Libc-583/string/strspn.3
@@ -47,17 +47,20 @@
 .Sh SYNOPSIS
 .In string.h
 .Ft size_t
-.Fn strspn "const char *s" "const char *charset"
+.Fo strspn
+.Fa "const char *s1"
+.Fa "const char *s2"
+.Fc
 .Sh DESCRIPTION
 The
 .Fn strspn
 function
 spans the initial part of the null-terminated string
-.Fa s
+.Fa s1 ,
 as long as the characters from
-.Fa s
+.Fa s1
 occur in string
-.Fa charset .
+.Fa s2 .
 .Sh RETURN VALUES
 The
 .Fn strspn