READTEXT error

I can't figure out I continually get a msg 7124 error using READTEXT.
The script:
DECLARE @.TextfieldPtr varbinary(16)
DECLARE @.CommentsBytes int
SELECT @.TextfieldPtr = TEXTPTR(TextComments)
FROM Comments
WHERE CommentId = 25
SELECT @.CommentsBytes = DATALENGTH(TextComments)
FROM Comments
WHERE CommentId = 25
/*This returns a value of 17,830*/
SET TEXTSIZE @.CommentsBytes
READTEXT Comments.TextComments @.TextfieldPtr 0 @.CommentsBytes
The result:
**********
17830
Server: Msg 7124, Level 16, State 1, Line 19
The offset and length specified in the READTEXT statement is greater
than the actual data length of 8915.
***********
Why 8915, which is half of the actual size returned by the DATALENGTH()
function?If it is NVARCHAR, use DATALENGTH(column)/2
On 3/12/05 4:31 PM, in article
1110663061.251893.218680@.z14g2000cwz.googlegroups.com, "Rlane"
<rmathuln@.pacbell.net> wrote:

> I can't figure out I continually get a msg 7124 error using READTEXT.
> The script:
> DECLARE @.TextfieldPtr varbinary(16)
> DECLARE @.CommentsBytes int
> SELECT @.TextfieldPtr = TEXTPTR(TextComments)
> FROM Comments
> WHERE CommentId = 25
> SELECT @.CommentsBytes = DATALENGTH(TextComments)
> FROM Comments
> WHERE CommentId = 25
> /*This returns a value of 17,830*/
> SET TEXTSIZE @.CommentsBytes
> READTEXT Comments.TextComments @.TextfieldPtr 0 @.CommentsBytes
> The result:
> **********
> 17830
> Server: Msg 7124, Level 16, State 1, Line 19
> The offset and length specified in the READTEXT statement is greater
> than the actual data length of 8915.
> ***********
> Why 8915, which is half of the actual size returned by the DATALENGTH()
> function?
>