External Procedure with Windows "Handle" datatype

Question

hi all,
I want to create a external procedure which use windows kerne32.dll library and GetFileSize function which is in dll.
http://msdn.microsoft.com/en-us/library/aa364955(v=vs.85).aspx
as you can see in this link , GetFileSize has two parameter, first one is a HANDLE type, how can I assign this parameter ? String is not working.
DWORD WINAPI GetFileSize(
  __in       HANDLE hFile,
  __out_opt  LPDWORD lpFileSizeHigh
Create Or Replace Function GetSize (FileName Varchar2, P_Value in out pls_integer) Return binary_double As
Language C Library Mylib Name "GetFileSize"
parameters (FileName  by reference String, P_Value int, return double );
Declare
  X1 number ;
  X2 Pls_Integer;
  X Number;
Begin
  x2 := 40000000;
  X1 := Getsize('C:\b.sql', X2);
  X := X1;
  dbms_output.put_line('x: ' ||x);
End;
/I allways getting zero value, file is exists and its size is bigger than zero.
what am i doing wrong?

Answer 1

I don't know, Why you are using kernel32.dll to know the file size. This can be done very easily using UTL_FILE.
Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.3.0 - Production
With the Partitioning, OLAP and Data Mining options
SQL> CREATE OR REPLACE FUNCTION utl_filesize(pi_dir_name  IN VARCHAR2,
  2                                          pi_file_name IN VARCHAR2)
  3    RETURN NUMBER IS
  4    file_size NUMBER;
  5    blk_size  BINARY_INTEGER;
  6    fexists   BOOLEAN;
  7  BEGIN
  8    UTL_FILE.fgetattr(pi_dir_name,
  9                      pi_file_name,
10                      fexists,
11                      file_size,
12                      blk_size);
13    RETURN file_size;
14  END utl_filesize;
15  /
Function created.
SQL> SELECT utl_filesize('SAUBHIK','test2.csv') "Size in Bytes" FROM dual;
Size in Bytes
           61
SQL> SELECT utl_filesize('SAUBHIK','Winter.jpg') "Size in Bytes" FROM dual;
Size in Bytes
       105542
SQL> Now, coming to your actual question.
This is a demo, How to call kernel32.dll from PL/SQL.*
By the way, I have copied kernel32.dll from C:\WINDOWS\system32 to C:\oracle\product\10.2.0\db_3\bin
My listener.ora setup
SID_LIST_LISTENEREXTPROC =
  (SID_LIST =
    (SID_DESC =
      (PROGRAM = extproc)
      (ENV = "EXTPROC_DLLS=ONLY:C:\oracle\product\10.2.0\db_3\bin\kernel32.dll")
      (SID_NAME = extproc)
      (ORACLE_HOME = C:\oracle\product\10.2.0\db_3)
  )My tnsnames.ora setup
EXTPROC_CONNECTION_DATA =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1))
    (CONNECT_DATA =
      (SID = PLSExtProc)
      (PRESENTATION = RO)
  )A little verification.
LSNRCTL> stop  LISTENEREXTPROC
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=extproc)))
The command completed successfully
LSNRCTL> start LISTENEREXTPROC
Starting tnslsnr: please wait...
TNSLSNR for 32-bit Windows: Version 10.2.0.3.0 - Production
System parameter file is C:\oracle\product\10.2.0\db_3\network\admin\listener.o
a
Log messages written to C:\oracle\product\10.2.0\db_3\network\log\listenerextpr
c.log
Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(PIPENAME=\\.\pipe\extprocipc
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=extproc)))
STATUS of the LISTENER
Alias                     LISTENEREXTPROC
Version                   TNSLSNR for 32-bit Windows: Version 10.2.0.3.0 - Prod
ction
Start Date                21-JAN-2011 17:32:26
Uptime                    0 days 0 hr. 0 min. 3 sec
Trace Level               off
Security                  ON: Local OS Authentication
SNMP                      OFF
Listener Parameter File   C:\oracle\product\10.2.0\db_3\network\admin\listener.
ra
Listener Log File         C:\oracle\product\10.2.0\db_3\network\log\listenerext
roc.log
Listening Endpoints Summary...
  (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(PIPENAME=\\.\pipe\extprocipc)))
Services Summary...
Service "extproc" has 1 instance(s).
  Instance "extproc", status UNKNOWN, has 1 handler(s) for this service...
The command completed successfully
LSNRCTL> exit
C:\Documents and Settings\Administrator>
C:\>tnsping EXTPROC_CONNECTION_DATA
TNS Ping Utility for 32-bit Windows: Version 10.2.0.3.0 - Production on 21-JAN-2
011 21:53:10
Copyright (c) 1997, 2006, Oracle.  All rights reserved.
Used parameter files:
C:\oracle\product\10.2.0\db_3\network\admin\sqlnet.ora
Used TNSNAMES adapter to resolve the alias
Attempting to contact (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = IPC)
(KEY = EXTPROC1))) (CONNECT_DATA = (SID = PLSExtProc) (PRESENTATION = RO)))
OK (70 msec)
C:\>Now, the actual codes.
SQL> CREATE OR REPLACE LIBRARY kernel32 AS 'C:\oracle\product\10.2.0\db_3\bin\kernel32.dll';
  2  /
Library created.
SQL> CREATE OR REPLACE FUNCTION CreateFile (FileName VARCHAR2 --1
  2                                         ,p_DesiredAccess BINARY_INTEGER --2
  3                                         ,p_ShareMode BINARY_INTEGER --3
  4                                         ,p_SecurityAttributes BINARY_INTEGER --4
  5                                         ,p_CreationDisposition BINARY_INTEGER --5
  6                                         ,p_FlagsAndAttributes BINARY_INTEGER --6
  7                                         ,p_TemplateFile BINARY_INTEGER )--7
  8  Return BINARY_INTEGER
  9   IS EXTERNAL
10  LIBRARY kernel32 Name "CreateFileA"
11  PARAMETERS (FileName STRING 
12              ,p_DesiredAccess long
13              ,p_ShareMode long
14              ,p_SecurityAttributes long
15              ,p_CreationDisposition long
16              ,p_FlagsAndAttributes long
17              ,p_TemplateFile long
18              ,return long );
19  /
Function created.
SQL> /* This is for closing the handle after use. */
SQL> CREATE OR REPLACE FUNCTION CloseFile (p_FileHandle BINARY_INTEGER)
  2                                        Return BINARY_INTEGER
  3   IS EXTERNAL
  4   LIBRARY kernel32 Name "CloseHandle"
  5   PARAMETERS (p_FileHandle long, return long);
  6  /
Function created.
SQL> /* This is the main function for getting size */
SQL> CREATE OR REPLACE FUNCTION GetSize (p_FileHandle BINARY_INTEGER,
  2                                      p_FileSizeHigh IN OUT BINARY_INTEGER)
  3                                      RETURN BINARY_INTEGER
  4   IS EXTERNAL
  5  LIBRARY kernel32 NAME "GetFileSize"
  6  PARAMETERS (p_FileHandle long, p_FileSizeHigh long, return long );
  7  /
Function created.
SQL> set serverout on
SQL> DECLARE
  2    v_FileSize BINARY_INTEGER;
  3    v_FileSizeHigh PLS_INTEGER;
  4    v_FileHandle BINARY_INTEGER;
  5    v_filename VARCHAR2(500) :='C:\test2.csv';
  6    v_dummy BINARY_INTEGER;
  7  BEGIN
  8    v_FileSizeHigh := 400000000;
  9    v_FileHandle:=CreateFile(v_filename -- File name
10                             ,0 -- Type of access required (read/write ect)
11                             ,0 -- disable share mode
12                             ,0 --no securoty attribute
13                             ,3 -- Means Open existing
14                             ,128 --080h, File attribute normal.
15                             ,0); --7
16    v_FileSize := Getsize(v_FileHandle, v_FileSizeHigh);
17    DBMS_OUTPUT.put_line('File Size in Bytes: ' ||v_FileSize);
18    v_dummy:=CloseFile(v_FileHandle);
19  END;
20  /
File Size in Bytes: 61
PL/SQL procedure successfully completed.
SQL>
SQL>
SQL> DECLARE
  2    v_FileSize BINARY_INTEGER;
  3    v_FileSizeHigh PLS_INTEGER;
  4    v_FileHandle BINARY_INTEGER;
  5    v_filename VARCHAR2(500) :='C:\Winter.jpg';
  6    v_dummy BINARY_INTEGER;
  7  BEGIN
  8    v_FileSizeHigh := 400000000;
  9    v_FileHandle:=CreateFile(v_filename -- File name
10                             ,0 -- Type of access required (read/write ect)
11                             ,0 -- disable share mode
12                             ,0 --no securoty attribute
13                             ,3 -- Means Open existing
14                             ,128 --080h, File attribute normal.
15                             ,0); --7
16    v_FileSize := Getsize(v_FileHandle, v_FileSizeHigh);
17    DBMS_OUTPUT.put_line('File Size in Bytes: ' ||v_FileSize);
18    v_dummy:=CloseFile(v_FileHandle);
19  END;
20  /
File Size in Bytes: 105542
PL/SQL procedure successfully completed.
SQL> Verification.
C:\>dir test2.csv
Volume in drive C has no label.
Volume Serial Number is 6806-ABBD
Directory of C:\
12/15/2010  01:35 PM                61 test2.csv
               1 File(s)             61 bytes
               0 Dir(s)   3,405,336,576 bytes free
C:\>dir Winter.jpg
Volume in drive C has no label.
Volume Serial Number is 6806-ABBD
Directory of C:\
10/11/2010  05:27 PM           105,542 Winter.jpg
               1 File(s)        105,542 bytes
               0 Dir(s)   3,405,336,576 bytes free
C:\>