diff --git a/qse/include/qse/sed/Sed.hpp b/qse/include/qse/sed/Sed.hpp
index b391fe17..3a7fe314 100644
--- a/qse/include/qse/sed/Sed.hpp
+++ b/qse/include/qse/sed/Sed.hpp
@@ -37,8 +37,9 @@ class Sed: public Mmgr
 {
 public:
 	typedef qse_sed_t sed_t;
-	typedef qse_sed_io_cmd_t sed_io_cmd_t;
-	typedef qse_sed_io_arg_t sed_io_arg_t;
+	typedef qse_sed_errnum_t errnum_t;
+	typedef qse_sed_io_cmd_t io_cmd_t;
+	typedef qse_sed_io_arg_t io_arg_t;
 
 	/**
 	 * The Sed() function creates a uninitialized stream editor.
@@ -102,7 +103,7 @@ public:
 	 * error occurred. It returns 0 if the stream editor has not been
 	 * initialized with the open function.
 	 */
-	int getErrorNumber () const;
+	errnum_t getErrorNumber () const;
 
 protected:
 	/**
@@ -123,7 +124,7 @@ protected:
 		};
 
 	protected:
-		IO (sed_io_arg_t* arg, Mode mode): arg(arg), mode (mode) {}
+		IO (io_arg_t* arg, Mode mode): arg(arg), mode (mode) {}
 
 	public:
 		/**
@@ -159,7 +160,7 @@ protected:
 		}
 
 	protected:
-		sed_io_arg_t* arg;
+		io_arg_t* arg;
 		Mode mode;
 	};
 
@@ -171,7 +172,7 @@ protected:
 	{
 	protected:
 		friend class Sed;
-		Console (sed_io_arg_t* arg, Mode mode): IO (arg, mode) {}
+		Console (io_arg_t* arg, Mode mode): IO (arg, mode) {}
 	};
 
 	/**
@@ -182,7 +183,7 @@ protected:
 	{
 	protected:
 		friend class Sed;
-		File (sed_io_arg_t* arg, Mode mode): IO (arg, mode) {}
+		File (io_arg_t* arg, Mode mode): IO (arg, mode) {}
 
 	public:
 		/**
@@ -218,10 +219,8 @@ protected:
 	sed_t* sed;
 
 private:
-	static ssize_t xin (
-		sed_t* s, sed_io_cmd_t cmd, sed_io_arg_t* arg) throw ();
-	static ssize_t xout (
-		sed_t* s, sed_io_cmd_t cmd, sed_io_arg_t* arg) throw ();
+	static ssize_t xin (sed_t* s, io_cmd_t cmd, io_arg_t* arg) throw ();
+	static ssize_t xout (sed_t* s, io_cmd_t cmd, io_arg_t* arg) throw ();
 };
 
 /////////////////////////////////
diff --git a/qse/include/qse/sed/sed.h b/qse/include/qse/sed/sed.h
index 97ece4bb..337844e9 100644
--- a/qse/include/qse/sed/sed.h
+++ b/qse/include/qse/sed/sed.h
@@ -70,7 +70,7 @@ enum qse_sed_errnum_t
 	QSE_SED_EREXMA,  /**< regular expression match error */
 	QSE_SED_EA1PHB,  /**< address 1 prohibited */
 	QSE_SED_EA2PHB,  /**< address 2 prohibited */
-	QSE_SED_EASTEP,  /**< invalid step address */
+	QSE_SED_EA2MOI,  /**< address 2 missing or invalid */
 	QSE_SED_ENEWLN,  /**< a new line is expected */
 	QSE_SED_EBSEXP,  /**< \ is expected */
 	QSE_SED_EBSDEL,  /**< \ used a delimiter */
@@ -92,6 +92,13 @@ enum qse_sed_errnum_t
 };
 typedef enum qse_sed_errnum_t qse_sed_errnum_t;
 
+/**
+ * The qse_sed_errstr_t type defines a prototype for an error string getter.
+ */
+typedef const qse_char_t* (*qse_sed_errstr_t) (
+	qse_sed_t* sed, qse_sed_errnum_t errnum
+);
+
 /** 
  * The qse_sed_option_t type defines various option codes for a stream editor.
  * Options can be XOR'ed with each other and be passed to a stream editor with
@@ -200,11 +207,26 @@ void qse_sed_setoption (
 	int        opt  /**< 0 or a number XOR'ed of qse_sed_option_t values */
 );
 
+/**
+ * The qse_sed_geterrstr() gets an error string getter.
+ */
+qse_sed_errstr_t qse_sed_geterrstr (
+	qse_sed_t*       sed    /**< a stream editor */
+);
+
+/**
+ * The qse_sed_seterrstr() sets an error string getter.
+ */
+void qse_sed_seterrstr (
+	qse_sed_t*       sed,   /**< a stream editor */
+	qse_sed_errstr_t errstr /**< an error string getter */
+);
+
 /**
  * The qse_sed_geterrnum() function gets the number of the last error.
  * @return the number of the last error
  */
-int qse_sed_geterrnum (
+qse_sed_errnum_t qse_sed_geterrnum (
 	qse_sed_t* sed /**< a stream editor */
 );
 
@@ -232,7 +254,7 @@ const qse_char_t* qse_sed_geterrmsg (
  */
 void qse_sed_geterror (
 	qse_sed_t*         sed,    /**< a stream editor */
-	int*               errnum, /**< a pointer to an error number holder */
+	qse_sed_errnum_t*  errnum, /**< a pointer to an error number holder */
 	qse_size_t*        errlin, /**< a pointer to an error line holder */
 	const qse_char_t** errmsg  /**< a pointer to an error message */
 );
@@ -244,7 +266,7 @@ void qse_sed_geterror (
  */
 void qse_sed_seterror (
 	qse_sed_t*        sed,    /**< a stream editor */
-	int               errnum, /**< an error number */
+	qse_sed_errnum_t  errnum, /**< an error number */
 	qse_size_t        errlin, /**< an error line */
 	const qse_cstr_t* errarg  /**< a string array for formatting an error message */
 );