Problems with fetching CLOB as ref cursor

[rovshan]

Hi,

First of all I wanted to say a big thank you to the author of OCILIB for
creating such a useful and intuitive library! I'm currently working on a
project where OCILIB makes my daily work much easier.

Currently I encountered one issue that I wanted to ask help for.

I use following PL/SQL block to get table DDL:

declare
    h1      NUMBER;         -- handle returned by OPEN
    th      NUMBER;         -- handle returned by ADD_TRANSFORM for DDL
    ddl     CLOB;           -- DDL
begin

 h1 := DBMS_METADATA.OPEN(:object_type);
 DBMS_METADATA.SET_FILTER(h1,'NAME', :object_name);
 DBMS_METADATA.SET_FILTER(h1,'SCHEMA', :owner);

 th := DBMS_METADATA.ADD_TRANSFORM(h1,'DDL');

 if :p_pretty = 'y' then
   DBMS_METADATA.SET_TRANSFORM_PARAM (th, 'PRETTY', TRUE);
 elsif :p_pretty = 'n' then
   DBMS_METADATA.SET_TRANSFORM_PARAM (th, 'PRETTY', FALSE);
 end if;

 /*rest of transformations similar to above if statement*/

 ddl := DBMS_METADATA.FETCH_CLOB(h1);

 DBMS_METADATA.CLOSE(h1);

 open :rs_out for select ddl from dual;
end;

Then in OCILIB I use

ociBoundStatement=OCI_StatementCreate(ociConnection);
OCI_BindStatement(ociStatement, L":rs_out", ociBoundStatement);
...execute...
OCI_Resultset *ociResultSet=OCI_GetResultset(ociBoundStatement);

to get the resultset (:rs_out).

After this I use a loop and call

toQString(OCI_GetString(ociResultset, colIx))

to get CLOB as a string (toQString is my function that converts the string to
QString).

On Linux everything works right, but on Windows it crashes approximately every
3 times out of 5. When I run it in debugger it crashes every time. Debugger
says there is a heap corruption and visual studio shows some assembly code
inside OCI_GetString. Also when I change CLOB to VARCHAR2 in PL/SQL block it
works right both on Linux and Windows. Because of this I thought if it works
with VARCHAR2 may be it is a bug related to CLOB handing on Windows. If you
encountered this issue or know the solution any help would be of great use for
me. If I'm asking a dummy question please, direct me in the right direction (I
tried with OCILIB 3.9.2 with Unicode build)

Thanks in advance!
Rovshan

[Vincent Rogier]

hi,

I'll hve a loot this evening and let you know.

regards,

vince

[Vincent Rogier]

Hi,

I found the problem. I'll make fix asap.

Send me your email that i can send you a win32 package to test.

vince

[Vincent Rogier]

Hi,

in lob.c, comment or remove the lines 433-436 :

// if (OCILib.nls_utf8 == FALSE)
// {
// byte_offset *= sizeof(odtext);
// }

it will work then as expected...

Regards

vince

[Nobody/Anonymous]

My email address is: rovshanb at gmail dot com

I will compile it and post the outcome here.

Thank you very very much!!!

[rovshan]

Yes it worked!

Thank you very much for your time and efforts and for giving this great
library to us for free!