diff --git a/ext/shadow/extconf.rb b/ext/shadow/extconf.rb
index 3e74834..730acf3 100644
--- a/ext/shadow/extconf.rb
+++ b/ext/shadow/extconf.rb
@@ -6,8 +6,6 @@
 
 require 'mkmf'
 
-$CFLAGS = RUBY_VERSION =~ /1\.8/ ? '-DRUBY18' : ''
-
 if( ! (ok = have_library("shadow","getspent")) )
   ok = have_func("getspent")
 end
@@ -19,8 +17,6 @@
 ok &= have_func("ulckpwdf")
 
 if ok
-  if ! have_func("sgetspent")
-    $CFLAGS += '-DSOLARIS'
-  end
+  have_func("sgetspent")
   create_makefile("shadow")
 end
diff --git a/ext/shadow/shadow.c b/ext/shadow/shadow.c
index 63fdd18..56faab0 100644
--- a/ext/shadow/shadow.c
+++ b/ext/shadow/shadow.c
@@ -10,16 +10,16 @@
 
 #include <shadow.h>
 #include "ruby.h"
-#ifdef RUBY18
+#ifndef HAVE_RUBY_IO_H
 #include "rubyio.h"
 #else
 #include <ruby/io.h>
 #endif
 
-#ifdef RUBY18
-#define file_ptr(x) (x)->f
+#ifdef GetReadFile
+#define file_ptr(x) GetReadFile(x)
 #else
-#define file_ptr(x) (x)->stdio_file
+#define file_ptr(x) rb_io_stdio_file(x)
 #endif
 
 static VALUE rb_mShadow;
@@ -35,7 +35,7 @@ rb_shadow_setspent(VALUE self)
 {
   setspent();
   return Qnil;
-};
+}
 
 
 static VALUE
@@ -43,10 +43,10 @@ rb_shadow_endspent(VALUE self)
 {
   endspent();
   return Qnil;
-};
+}
 
 
-#ifndef SOLARIS
+#ifdef HAVE_SGETSPENT
 static VALUE
 rb_shadow_sgetspent(VALUE self, VALUE str)
 {
@@ -74,7 +74,7 @@ rb_shadow_sgetspent(VALUE self, VALUE str)
 		      0);
   free(entry);
   return result;
-};
+}
 #endif
 
 static VALUE
@@ -103,7 +103,7 @@ rb_shadow_fgetspent(VALUE self, VALUE file)
 		      INT2FIX(entry->sp_flag),
 		      0);
   return result;
-};
+}
 
 static VALUE
 rb_shadow_getspent(VALUE self)
@@ -128,7 +128,7 @@ rb_shadow_getspent(VALUE self)
 		      INT2FIX(entry->sp_flag),
 		      0);
   return result;
-};
+}
 
 static VALUE
 rb_shadow_getspnam(VALUE self, VALUE name)
@@ -156,7 +156,7 @@ rb_shadow_getspnam(VALUE self, VALUE name)
 		      INT2FIX(entry->sp_flag),
 		      0);
   return result;
-};
+}
 
 
 static VALUE
@@ -188,7 +188,7 @@ rb_shadow_putspent(VALUE self, VALUE entry, VALUE file)
     rb_raise(rb_eStandardError,"can't change password");
 
   return Qtrue;
-};
+}
 
 
 static VALUE
@@ -200,7 +200,7 @@ rb_shadow_lckpwdf(VALUE self)
     rb_raise(rb_eFileLock,"password file was locked");
   else
     return Qtrue;
-};
+}
 
 static int in_lock;
 
@@ -209,7 +209,7 @@ rb_shadow_lock(VALUE self)
 {
   int result;
 
-  if( rb_iterator_p() ){
+  if( rb_block_given_p() ){
     result = lckpwdf();
     if( result == -1 ){
       rb_raise(rb_eFileLock,"password file was locked");
@@ -219,13 +219,13 @@ rb_shadow_lock(VALUE self)
       rb_yield(Qnil);
       in_lock--;
       ulckpwdf();
-    };
+    }
     return Qtrue;
   }
   else{
     return rb_shadow_lckpwdf(self);
-  };
-};
+  }
+}
 
 
 static VALUE
@@ -233,16 +233,16 @@ rb_shadow_ulckpwdf(VALUE self)
 {
   if( in_lock ){
     rb_raise(rb_eFileLock,"you call unlock method in lock iterator.");
-  };
+  }
   ulckpwdf();
   return Qtrue;
-};
+}
 
 static VALUE
 rb_shadow_unlock(VALUE self)
 {
   return rb_shadow_ulckpwdf(self);
-};
+}
 
 static VALUE
 rb_shadow_lock_p(VALUE self)
@@ -256,12 +256,12 @@ rb_shadow_lock_p(VALUE self)
   else{
     ulckpwdf();
     return Qfalse;
-  };
-};
+  }
+}
 
 
 void
-Init_shadow()
+Init_shadow(void)
 {
   rb_sPasswdEntry = rb_struct_define("PasswdEntry",
 				     "sp_namp","sp_pwdp","sp_lstchg",
@@ -280,7 +280,7 @@ Init_shadow()
 
   rb_define_module_function(rb_mPasswd,"setspent",rb_shadow_setspent,0);
   rb_define_module_function(rb_mPasswd,"endspent",rb_shadow_endspent,0);
-#ifndef SOLARIS
+#ifdef HAVE_SGETSPENT
   rb_define_module_function(rb_mPasswd,"sgetspent",rb_shadow_sgetspent,1);
 #endif
   rb_define_module_function(rb_mPasswd,"fgetspent",rb_shadow_fgetspent,1);
@@ -292,4 +292,4 @@ Init_shadow()
   rb_define_module_function(rb_mPasswd,"ulckpwdf",rb_shadow_ulckpwdf,0);
   rb_define_module_function(rb_mPasswd,"unlock",rb_shadow_unlock,0);
   rb_define_module_function(rb_mPasswd,"lock?",rb_shadow_lock_p,0);
-};
+}