Home » Developer & Programmer » Forms » ora_ffi.find_library/load_library cannot find/open USER32.DLL (Win XP, 11g 11.1.2.1.0)
ora_ffi.find_library/load_library cannot find/open USER32.DLL [message #605360] |
Wed, 08 January 2014 17:44 ![Go to next message Go to next message](/forum/theme/orafaq/images/down.png) |
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aleech1029
Messages: 2 Registered: January 2014 Location: Denver
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Junior Member |
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I am running forms locally on my machine out of developer 11.1.2.1.0 - ora_ffi.find_library('USER32.DLL') and ora_ffi.load_library(NULL,'USER32.DLL) throw an exception 'cannot open library USER32.DLL' - I have checked my PATH variable and c:\Windows\System32 is included - additionally I have modified the code to explicitly reference the directory and still no luck
I believe that I have followed the configuration of webutil to the letter
my apologies up front if this has be previously posted...I have scoured the internet without resolution
Thank you in advance
[Updated on: Wed, 08 January 2014 17:45] Report message to a moderator
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Re: ora_ffi.find_library/load_library cannot find/open USER32.DLL [message #605466 is a reply to message #605360] |
Thu, 09 January 2014 11:13 ![Go to previous message Go to previous message](/forum/theme/orafaq/images/up.png) ![Go to next message Go to next message](/forum/theme/orafaq/images/down.png) |
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mughals_king
Messages: 392 Registered: January 2012 Location: pakistan
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Senior Member |
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i can provide some stuff i hope this could help you.
here's an ORA_FFI A Worked Example DLL-> Trigger example.
1. The C Code that is the DLL function:
----------------------------------------
#include <string.h>
#include <windows.h>
//Simple C function that just puts something in a string
// and returns the length of that string both as the RC and as a param
// Keeping the C interface as simple as possible.
// The function is exported from the DLL
// You can use the Visual C utility DUMPBIN to check that the
// Function is correctly exported.
__declspec( dllexport ) int PopulateString ( char *FormsBuffer, int *BuffLen)
{
int LocalLength;
strcpy(FormsBuffer,"A Fixed string from within the C program");
*BuffLen = strlen(FormsBuffer);
LocalLength = strlen(FormsBuffer);
return LocalLength;
}
2. The package Header for the FFI code:
----------------------------------------
PACKAGE FFISample IS
/* So this is the Pubic Interface */
FUNCTION PopulateString ( PopulateString IN OUT VARCHAR2,
BuffLen IN OUT PLS_INTEGER)
RETURN PLS_INTEGER;
END FFISample;
3. The package Body for the FFI code:
--------------------------------------
PACKAGE BODY FFISample IS
-- Define the various Handles
lh_ffisamp ora_ffi.libHandleType;
fh_PopulateString ora_ffi.funcHandleType;
-- Define internal versions of the functions
/* The interface function, note how the C Pointers map to
IN OUT variables! */
FUNCTION i_PopulateString ( funcHandle IN ora_ffi.funcHandleType,
PopulateString IN OUT VARCHAR2,
BuffLen IN OUT PLS_INTEGER)
RETURN PLS_INTEGER;
-- interface the internal function to the C call interface
PRAGMA INTERFACE(C,i_PopulateString,11265);
-- Body of the Externalised function
FUNCTION PopulateString ( PopulateString IN OUT VARCHAR2,
BuffLen IN OUT PLS_INTEGER)
RETURN PLS_INTEGER IS
-- declare the buffer padded to the max possible length of the string
-- This is an In Out var so PopulateString may already have some
-- content
/* This RPAD ensures that the VARCHAR string occupies
contiguous memory */
PopulateString_l VARCHAR2(255) :=
RPAD(SUBSTR(NVL(PopulateString,' '),1,255),255,CHR(0));
-- internal buffer for the Int no padding required here.
BuffLen_l PLS_INTEGER := BuffLen;
rc PLS_INTEGER;
BEGIN
-- Call the internal version of the function with the local buffers
rc := i_PopulateString( fh_PopulateString, PopulateString_l, BuffLen_l);
-- Reset the Real variables with the contents of the buffer
PopulateString := PopulateString_l;
BuffLen := BuffLen_l;
RETURN (rc);
END ;
-- Package Body Block, handles loading the DLL into memory and registering the
Functions
BEGIN
BEGIN
-- Try and fin the DLL already loaded
lh_ffisamp := ora_ffi.find_library('ffisamp.dll');
EXCEPTION WHEN ora_ffi.FFI_ERROR THEN
-- Ok not found lets load it
-- The null argument for the LOAD library is the DLL location so if
-- the DLL was not in
-- the working DIR or not in the PATH soemwhere we might want to
-- put something in here.
lh_ffisamp := ora_ffi.load_library(NULL,'ffisamp.dll');
END ;
-- Now register the PopulateString
fh_PopulateString := ora_ffi.register_function(lh_ffisamp,
'PopulateString',ora_ffi.C_STD);
ora_ffi.register_parameter(fh_PopulateString,ORA_FFI.C_CHAR_PTR);
ora_ffi.register_parameter(fh_PopulateString,ORA_FFI.C_INT_PTR);
ora_ffi.register_return(fh_PopulateString,ORA_FFI.C_INT);
EXCEPTION /* Generic FFI Error Handler to unwind the TOOL_ERR stack */
when others then
for iCounter in 1..tool_err.nerrors LOOP
message(tool_err.message);
tool_err.pop;
end loop;
END FFISample;
4. Finally a sample forms trigger that calls the C code:
---------------------------------------------------------
(this might be say on a When-Button-Pressed trigger)
declare
StringBuffer varchar2(255)
:= 'An initial value that will be overwritten';
StringLength pls_integer := length(StringBuffer);
RC pls_integer;
begin
message('Before Calling My c the value of the string is:'||
StringBuffer);
message('Old Length '||to_char(StringLength));
RC := FFISample.PopulateString(StringBuffer,StringLength);
message('The New value for String is: '||StringBuffer);
message('New Length '||to_char(StringLength));
message('RC was '||to_char(RC));
end;
.
the end.
another doc, may be useful:
ORAFFI: PASSING CHARACTER STRING POINTERS BACK FROM ORA_FFI FUNCTIONS
Problem Description:
====================
You need know the details on passing a character string pointer (char*) back
from a function into ORA_FFI.
Symptoms of improper implementations of this may be a GPF in DE15WIN.DLL.
Related Terms:
==============
ORAFFI
PTR
LPCTSTR
DLL
Solution Description:
=====================
The memory for the char pointer must be globally allocated using a GlobalAlloc
(with the GMEM_FIXED flag) such that the memory is not resident on the stack.
The problem with allocating memory on the stack for the pointer is that this
memory block will be freed when the function exits and the returned pointer
will become invalid.
Here is a complete example showing a successful implementation of this
functionality. Although the following code demonstrates a 16bit
implementation, the same holds true for 32bit implementations.
-- ********************************************************* --
-- This calling trigger's code --
-- ********************************************************* --
declare
-- Parameters
parm1 VARCHAR2(128) := 'X';
-- Return value
rt VARCHAR2(512) := 'Hello Folks';
begin
rt := MyLib.MyFunc1( parm1 );
Message(rt);
end;
-- ********************************************************* --
-- This wrapper package's header --
-- ********************************************************* --
PACKAGE MyLib IS
FUNCTION MyFunc1( parm1 IN OUT VARCHAR2 )
RETURN VARCHAR2;
END;
-- ********************************************************* --
-- This wrapper package's body --
-- ********************************************************* --
PACKAGE BODY MyLib IS
lib_hndl ora_ffi.libHandleType;
func_hndl ora_ffi.funcHandleType;
FUNCTION i_MyFunc1( func_hndl IN ora_ffi.funcHandleType,
parm1 IN OUT VARCHAR2 )
RETURN VARCHAR2;
PRAGMA INTERFACE(C,i_MyFunc1,11265);
FUNCTION MyFunc1( parm1 IN OUT VARCHAR2 )
RETURN VARCHAR2
IS
parm1_l VARCHAR2 := parm1;
rc VARCHAR2(512);
BEGIN
rc := i_MyFunc1(func_hndl, parm1_l);
RETURN (rc);
END ;
BEGIN
lib_hndl := ora_ffi.load_library(NULL,'DLL16.DLL');
func_hndl :=
ora_ffi.register_function(lib_hndl,'PASCAL_TEST',ora_ffi.PASCAL_STD);
ora_ffi.register_parameter(func_hndl,ORA_FFI.C_CHAR_PTR);
ora_ffi.register_return(func_hndl,ORA_FFI.C_CHAR_PTR);
END;
-- ********************************************************* --
-- This DLL's DEF file --
-- ********************************************************* --
LIBRARY DLL16
EXETYPE WINDOWS
CODE PRELOAD MOVEABLE DISCARDABLE
DATA PRELOAD SINGLE
HEAPSIZE 4096
EXPORTS
WEP PRIVATE
Pascal_Test @1
-- ********************************************************* --
-- This DLL's CPP file --
-- ********************************************************* --
#include <windows.h>
#include <string.h>
int CALLBACK LibMain(HANDLE hInstance, WORD wDataSeg, WORD wHeapSize, LPSTR
lpszCmdLine)
{
if (wHeapSize > 0 )
UnlockData (0); // Unlocks the library's data segment
return 1;
}
char* FAR PASCAL __export Pascal_Test (char* xyz)
{
HGLOBAL hgl;
char FAR* abc;
hgl = GlobalAlloc(GPTR, 256);
abc = (char*)GlobalLock(hgl);
strcpy(abc,"Hello World");
GlobalUnlock(hgl);
MessageBox(NULL,abc,"Pascal",MB_OK);
return abc;
. the end.
more stuff, see ***** below on "scalar" only variables being support by ORA_FFI.
Problem Description:
====================
What is ORA_FFI?
Where do you find documentation on ORA_FFI?
What are the differences between ORA_FFI and user exits?
ORA_FFI ENABLES PL/SQL TO CALL 3GL ROUTINES IN EXTERNAL LIBRARIES
Solution Description:
=====================
This is an excerpt from the Oracle Procedure Builder Release Notes:
Q: What is ORA_FFI? Does it offer any benefits over user_exits?
A: ORA_FFI stands for Oracle Foreign Function Interface. It is a built-in
PL/SQL package that provides services for integrating with third-party
Dynamic Link Libraries.
The bindings from PL/SQL program units to foreign functions are
established DYNAMICALLY at runtime -- NOT compile time -- obviating
the need to relink executables each time updates are made.
Because bindings are dynamic, ORA_FFI provides a much more
extensible solution than user exits. If two companies wanted to
build forms applications that both had a user exit DLL, it was a
real problem because there can only be one forms user exit DLL
(F40XTB.DLL).
In addition, there are already many third-party DLLs available,
including the Windows API library. ORA_FFI enables developers
to integrate with these DLLs with little or no additional C
coding. User exits may require a substantial amount of C coding
apart from the work that still must be done in PL/SQL.
Note: The ORA_FFI call is only available on the client side PL/SQL
engine, not the server side. Typically, it is used from the
Forms environment.
*******Q: Does ORA_FFI offer support for passing pointers or structures?
A: ORA_FFI only offers support for passing scalar values.
Many people do not consider this a hinderance because it is
relatively easy to write a small wrapper DLL. Functions in
this auxiliary DLL would accept arguments which are used to establish
the necessary structure(s) that gets passed to the primary
DLL.
Also, there are already many useful Windows calls which do not
require structured arguments. For example, all of the Profile
functions (GetPrivateProfileString) do not require structured
arguments.
Q: Does ORA_FFI work on platforms other than Microsoft Windows?
A: ORA_FFI will work on any platform that supports dynamic loading.
Besides Windows, SunOS, VMS, and Mac are examples of other
platforms where developers can exploit ORA_FFI.
Additional Information:
=======================
Oracle Documentation:
---------------------
Oracle Procedure Builder 1.5 Developer's Guide Manual
Chapter 8, Oracle Procedure Builder Packages
The ORA_FFI Package
Oracle Support Bulletins:
-------------------------
9247635.61
CALLING WINDOWS APPLICATIONS FROM ORACLE FORMS 4.5
Oracle Web Sites:
-----------------
You can download examples along with the White Paper "Boosting Development
Productivity with Foreign Function Calls" from the following web sites:
16-bit
------
[url]ftp://support.oracle.com/desktop/download/woraffi.exe[/url]
32-bit
------
[url]ftp://support.oracle.com/desktop/download/ntoraffi.exe[/url]
If you have difficulties connecting to the server,
substitute the IP address for the server name (192.86.154.93).
Expert Comment
by: ORACLEtunePosted on 2002-06-22 at 16:33:40ID: 7101141
Rank: Master
more stuff, see ***** below on "scalar" only variables being support by ORA_FFI.
Problem Description:
====================
What is ORA_FFI?
Where do you find documentation on ORA_FFI?
What are the differences between ORA_FFI and user exits?
ORA_FFI ENABLES PL/SQL TO CALL 3GL ROUTINES IN EXTERNAL LIBRARIES
Solution Description:
=====================
This is an excerpt from the Oracle Procedure Builder Release Notes:
Q: What is ORA_FFI? Does it offer any benefits over user_exits?
A: ORA_FFI stands for Oracle Foreign Function Interface. It is a built-in
PL/SQL package that provides services for integrating with third-party
Dynamic Link Libraries.
The bindings from PL/SQL program units to foreign functions are
established DYNAMICALLY at runtime -- NOT compile time -- obviating
the need to relink executables each time updates are made.
Because bindings are dynamic, ORA_FFI provides a much more
extensible solution than user exits. If two companies wanted to
build forms applications that both had a user exit DLL, it was a
real problem because there can only be one forms user exit DLL
(F40XTB.DLL).
In addition, there are already many third-party DLLs available,
including the Windows API library. ORA_FFI enables developers
to integrate with these DLLs with little or no additional C
coding. User exits may require a substantial amount of C coding
apart from the work that still must be done in PL/SQL.
Note: The ORA_FFI call is only available on the client side PL/SQL
engine, not the server side. Typically, it is used from the
Forms environment.
*******Q: Does ORA_FFI offer support for passing pointers or structures?
A: ORA_FFI only offers support for passing scalar values.
Many people do not consider this a hinderance because it is
relatively easy to write a small wrapper DLL. Functions in
this auxiliary DLL would accept arguments which are used to establish
the necessary structure(s) that gets passed to the primary
DLL.
Also, there are already many useful Windows calls which do not
require structured arguments. For example, all of the Profile
functions (GetPrivateProfileString) do not require structured
arguments.
Q: Does ORA_FFI work on platforms other than Microsoft Windows?
A: ORA_FFI will work on any platform that supports dynamic loading.
Besides Windows, SunOS, VMS, and Mac are examples of other
platforms where developers can exploit ORA_FFI.
Additional Information:
=======================
Oracle Documentation:
---------------------
Oracle Procedure Builder 1.5 Developer's Guide Manual
Chapter 8, Oracle Procedure Builder Packages
The ORA_FFI Package
Oracle Support Bulletins:
-------------------------
9247635.61
CALLING WINDOWS APPLICATIONS FROM ORACLE FORMS 4.5
Oracle Web Sites:
-----------------
You can download examples along with the White Paper "Boosting Development
Productivity with Foreign Function Calls" from the following web sites:
16-bit
------
[url]ftp://support.oracle.com/desktop/download/woraffi.exe[/url]
32-bit
------
[url]ftp://support.oracle.com/desktop/download/ntoraffi.exe[/url]
If you have difficulties connecting to the server,
substitute the IP address for the server name (192.86.154.93).
more stuff, see ***** below on "scalar" only variables being support by ORA_FFI.
Problem Description:
====================
What is ORA_FFI?
Where do you find documentation on ORA_FFI?
What are the differences between ORA_FFI and user exits?
ORA_FFI ENABLES PL/SQL TO CALL 3GL ROUTINES IN EXTERNAL LIBRARIES
Solution Description:
=====================
This is an excerpt from the Oracle Procedure Builder Release Notes:
Q: What is ORA_FFI? Does it offer any benefits over user_exits?
A: ORA_FFI stands for Oracle Foreign Function Interface. It is a built-in
PL/SQL package that provides services for integrating with third-party
Dynamic Link Libraries.
The bindings from PL/SQL program units to foreign functions are
established DYNAMICALLY at runtime -- NOT compile time -- obviating
the need to relink executables each time updates are made.
Because bindings are dynamic, ORA_FFI provides a much more
extensible solution than user exits. If two companies wanted to
build forms applications that both had a user exit DLL, it was a
real problem because there can only be one forms user exit DLL
(F40XTB.DLL).
In addition, there are already many third-party DLLs available,
including the Windows API library. ORA_FFI enables developers
to integrate with these DLLs with little or no additional C
coding. User exits may require a substantial amount of C coding
apart from the work that still must be done in PL/SQL.
Note: The ORA_FFI call is only available on the client side PL/SQL
engine, not the server side. Typically, it is used from the
Forms environment.
*******Q: Does ORA_FFI offer support for passing pointers or structures?
A: ORA_FFI only offers support for passing scalar values.
Many people do not consider this a hinderance because it is
relatively easy to write a small wrapper DLL. Functions in
this auxiliary DLL would accept arguments which are used to establish
the necessary structure(s) that gets passed to the primary
DLL.
Also, there are already many useful Windows calls which do not
require structured arguments. For example, all of the Profile
functions (GetPrivateProfileString) do not require structured
arguments.
Q: Does ORA_FFI work on platforms other than Microsoft Windows?
A: ORA_FFI will work on any platform that supports dynamic loading.
Besides Windows, SunOS, VMS, and Mac are examples of other
platforms where developers can exploit ORA_FFI.
Additional Information:
=======================
Oracle Documentation:
---------------------
Oracle Procedure Builder 1.5 Developer's Guide Manual
Chapter 8, Oracle Procedure Builder Packages
The ORA_FFI Package
Oracle Support Bulletins:
-------------------------
9247635.61
CALLING WINDOWS APPLICATIONS FROM ORACLE FORMS 4.5
Oracle Web Sites:
-----------------
You can download examples along with the White Paper "Boosting Development
Productivity with Foreign Function Calls" from the following web sites:
16-bit
------
[url]ftp://support.oracle.com/desktop/download/woraffi.exe[/url]
32-bit
------
[url]ftp://support.oracle.com/desktop/download/ntoraffi.exe[/url]
If you have difficulties connecting to the server,
substitute the IP address for the server name (192.86.154.93).
more stuff, see ***** below on "scalar" only variables being support by ORA_FFI.
Problem Description:
====================
What is ORA_FFI?
Where do you find documentation on ORA_FFI?
What are the differences between ORA_FFI and user exits?
ORA_FFI ENABLES PL/SQL TO CALL 3GL ROUTINES IN EXTERNAL LIBRARIES
Solution Description:
=====================
This is an excerpt from the Oracle Procedure Builder Release Notes:
Q: What is ORA_FFI? Does it offer any benefits over user_exits?
A: ORA_FFI stands for Oracle Foreign Function Interface. It is a built-in
PL/SQL package that provides services for integrating with third-party
Dynamic Link Libraries.
The bindings from PL/SQL program units to foreign functions are
established DYNAMICALLY at runtime -- NOT compile time -- obviating
the need to relink executables each time updates are made.
Because bindings are dynamic, ORA_FFI provides a much more
extensible solution than user exits. If two companies wanted to
build forms applications that both had a user exit DLL, it was a
real problem because there can only be one forms user exit DLL
(F40XTB.DLL).
In addition, there are already many third-party DLLs available,
including the Windows API library. ORA_FFI enables developers
to integrate with these DLLs with little or no additional C
coding. User exits may require a substantial amount of C coding
apart from the work that still must be done in PL/SQL.
Note: The ORA_FFI call is only available on the client side PL/SQL
engine, not the server side. Typically, it is used from the
Forms environment.
*******Q: Does ORA_FFI offer support for passing pointers or structures?
A: ORA_FFI only offers support for passing scalar values.
Many people do not consider this a hinderance because it is
relatively easy to write a small wrapper DLL. Functions in
this auxiliary DLL would accept arguments which are used to establish
the necessary structure(s) that gets passed to the primary
DLL.
Also, there are already many useful Windows calls which do not
require structured arguments. For example, all of the Profile
functions (GetPrivateProfileString) do not require structured
arguments.
Q: Does ORA_FFI work on platforms other than Microsoft Windows?
A: ORA_FFI will work on any platform that supports dynamic loading.
Besides Windows, SunOS, VMS, and Mac are examples of other
platforms where developers can exploit ORA_FFI.
Additional Information:
=======================
Oracle Documentation:
---------------------
Oracle Procedure Builder 1.5 Developer's Guide Manual
Chapter 8, Oracle Procedure Builder Packages
The ORA_FFI Package
Oracle Support Bulletins:
-------------------------
9247635.61
CALLING WINDOWS APPLICATIONS FROM ORACLE FORMS 4.5
Oracle Web Sites:
-----------------
You can download examples along with the White Paper "Boosting Development
Productivity with Foreign Function Calls" from the following web sites:
16-bit
------
[url]ftp://support.oracle.com/desktop/download/woraffi.exe[/url]
32-bit
------
[url]ftp://support.oracle.com/desktop/download/ntoraffi.exe[/url]
If you have difficulties connecting to the server,
substitute the IP address for the server name (192.86.154.93).
Regard
Mughal
[Updated on: Thu, 09 January 2014 11:14] Report message to a moderator
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Re: ora_ffi.find_library/load_library cannot find/open USER32.DLL [message #605467 is a reply to message #605466] |
Thu, 09 January 2014 11:18 ![Go to previous message Go to previous message](/forum/theme/orafaq/images/up.png) |
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aleech1029
Messages: 2 Registered: January 2014 Location: Denver
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Junior Member |
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I should have been more specific in my original post - this code is legacy code and exists in a common library that is integral to our enterprise application. It's been around since at least 1998 and has worked without issue. I recently upgraded to Forms 11.1.2.1.0 and this code now throws an exception when running forms locally on my machine (Win XP) directly out of developer.
Still looking for suggestions/ideas...
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