* README.EXT: ditto.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@17146 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 8 insertions, 1 deletions

diff --git a/README.EXT b/README.EXT
index f93f82997e..daf67a5038 100644
--- a/README.EXT
+++ b/README.EXT
@@ -31,7 +31,7 @@ The Ruby interpreter has the following data types:
 	T_STRING	string
 	T_REGEXP	regular expression
 	T_ARRAY		array
-	T_FIXNUM	Fixnum(31bit integer)
+	T_FIXNUM	Fixnum(31bit or 63bit integer)
 	T_HASH		associative array
 	T_STRUCT	(Ruby) structure
 	T_BIGNUM	multi precision integer
@@ -106,6 +106,13 @@ representation of var.  These macros will skip the replacement if var
 is a String.  Notice that the macros take only the lvalue as their
 argument, to change the value of var in place.
 
+You can also use the macro named StringValueCStr(). This is just
+like StringValuePtr(), but always add nul character at the end of
+the result. If the result contains nul character, this macro causes
+the ArgumentError exception.
+StringValuePtr() doesn't gurantee to exist nul at the end of the
+result, and the result may contain nul.
+
 In version 1.6 or earlier, STR2CSTR() was used to do the same thing
 but now it is deprecated in version 1.7, because STR2CSTR() has a risk
 of a dangling pointer problem in the to_str() implicit conversion.