Unable to find an entry point named in DLL

[Prashant Bhuptani]

Hi Guys,

I am trying to use a C++ dll in VB.NET code.

I have imported the dll in the following manner:

<code>

Imports System.Runtime.InteropServices

Module modDllImport
<DllImport("hsec.dll")> _
Public Function sha1_hash(ByRef co As String, ByRef ci As String) As
Integer
End Function

<DllImport("aes.dll")> _
Public Function aes_enc(ByRef co As String, ByRef ci As String) As Integer
End Function
End Module

</code>

However when I call the exported method, I get the following error:

Unable to find an entry point named sha1_hash in DLL hsec.dll.
Description: An unhandled exception occurred during the execution of the
current web request. Please review the stack trace for more information
about the error and where it originated in the code.

Exception Details: System.EntryPointNotFoundException: Unable to find an
entry point named sha1_hash in DLL hsec.dll.
I am not sure where I am going wrong. The dlls are in my system32 folder as
well. I hope that .NET works with normal C/C++ dlls as well along with COM
dlls.

Any kind of help would be really appreciated.

Thanks,

Regards,
-Prashant

[Rahul Kapoor]

another victim of name mangling i suppose ;-)

c++ compiler will mangle names, when compiling the c++ the dll generate a
map file and look at the real names (in case you have the dll's source
surround the declarations with extern "C" blocks to stop the mangling)

you can also use the dumpbin tool to look at the actual exported function
names in the dll

HTH
Rahul
r_*****@nospam.yahoo.com


"Prashant Bhuptani" <pb*******@itstrategists.com> wrote in message
news:ef**************@TK2MSFTNGP09.phx.gbl...

Hi Guys,

I am trying to use a C++ dll in VB.NET code.

I have imported the dll in the following manner:

<code>

Imports System.Runtime.InteropServices

Module modDllImport
<DllImport("hsec.dll")> _
Public Function sha1_hash(ByRef co As String, ByRef ci As String) As
Integer
End Function

<DllImport("aes.dll")> _
Public Function aes_enc(ByRef co As String, ByRef ci As String) As Integer End Function
End Module

</code>

However when I call the exported method, I get the following error:

Unable to find an entry point named sha1_hash in DLL hsec.dll.
Description: An unhandled exception occurred during the execution of the
current web request. Please review the stack trace for more information
about the error and where it originated in the code.

Exception Details: System.EntryPointNotFoundException: Unable to find an
entry point named sha1_hash in DLL hsec.dll.
I am not sure where I am going wrong. The dlls are in my system32 folder as well. I hope that .NET works with normal C/C++ dlls as well along with COM
dlls.

Any kind of help would be really appreciated.

Thanks,

Regards,
-Prashant

[Herfried K. Wagner [MVP]]

* "Prashant Bhuptani" <pb*******@itstrategists.com> scripsit:

I am trying to use a C++ dll in VB.NET code.

I have imported the dll in the following manner:

<code>

Imports System.Runtime.InteropServices

Module modDllImport
<DllImport("hsec.dll")> _
Public Function sha1_hash(ByRef co As String, ByRef ci As String) As
Integer
End Function

<DllImport("aes.dll")> _
Public Function aes_enc(ByRef co As String, ByRef ci As String) As Integer
End Function
End Module

</code>

However when I call the exported method, I get the following error:

Unable to find an entry point named sha1_hash in DLL hsec.dll.
Description: An unhandled exception occurred during the execution of the
current web request. Please review the stack trace for more information
about the error and where it originated in the code.

Exception Details: System.EntryPointNotFoundException: Unable to find an
entry point named sha1_hash in DLL hsec.dll.

Can you post the "heads" of the C functions and the exports of the C
DLL?

--
Herfried K. Wagner
MVP · VB Classic, VB.NET
<http://www.mvps.org/dotnet>

<http://www.plig.net/nnq/nquote.html>

[Tom Shelton]

On 2003-11-06, Rahul Kapoor <sp**@nospam.com> wrote:

another victim of name mangling i suppose ;-)

c++ compiler will mangle names, when compiling the c++ the dll generate a
map file and look at the real names (in case you have the dll's source
surround the declarations with extern "C" blocks to stop the mangling)

Not if your using __stdcall. The best way to do it is to create a .def
file.

--
Tom Shelton
MVP [Visual Basic]

[Prashant Bhuptani]

Hi Herfried,

I have a test code in VC++ which calls the exported methods of these dlls.
These methods are declared in the header file as follows:

__declspec(dllexport) int sha1_hash(const unsigned char ci[],unsigned char
co[]);
__declspec(dllexport) int aes_enc(const unsigned char ci[],char co[]);

However, I don't have the code which is used to create the dll.
So as of now I am not sure how the .def file is created, but if that helps
in solving this problem, I can definitely find out.

Thanks,

Regards,
-Prashant


"Herfried K. Wagner [MVP]" <hi***************@gmx.at> wrote in message
news:bo*************@ID-208219.news.uni-berlin.de...

* "Prashant Bhuptani" <pb*******@itstrategists.com> scripsit:

I am trying to use a C++ dll in VB.NET code.

I have imported the dll in the following manner:

<code>

Imports System.Runtime.InteropServices

Module modDllImport
<DllImport("hsec.dll")> _
Public Function sha1_hash(ByRef co As String, ByRef ci As String) As
Integer
End Function

<DllImport("aes.dll")> _
Public Function aes_enc(ByRef co As String, ByRef ci As String) As Integer End Function
End Module

</code>

However when I call the exported method, I get the following error:

Unable to find an entry point named sha1_hash in DLL hsec.dll.
Description: An unhandled exception occurred during the execution of the
current web request. Please review the stack trace for more information
about the error and where it originated in the code.

Exception Details: System.EntryPointNotFoundException: Unable to find an
entry point named sha1_hash in DLL hsec.dll.

Can you post the "heads" of the C functions and the exports of the C
DLL?

--
Herfried K. Wagner
MVP · VB Classic, VB.NET
<http://www.mvps.org/dotnet>

<http://www.plig.net/nnq/nquote.html>

[Tom Shelton]

In article <u9*************@tk2msftngp13.phx.gbl>, Prashant Bhuptani wrote:

Hi Herfried,

I have a test code in VC++ which calls the exported methods of these dlls.
These methods are declared in the header file as follows:

__declspec(dllexport) int sha1_hash(const unsigned char ci[],unsigned char
co[]);
__declspec(dllexport) int aes_enc(const unsigned char ci[],char co[]);

However, I don't have the code which is used to create the dll.
So as of now I am not sure how the .def file is created, but if that helps
in solving this problem, I can definitely find out.

Thanks,

Regards,
-Prashant

do a dumpbin /exports on the dll to see the exported names of the
functions. More then likely, they are not sha1_enc and aes_enc. There
is generally type information appended to the names (I don't remember
the exact characters any more). The point is, if there is no .DEF file
for the functions, the names actually get changed by the compiler. To
use them from VB.NET, you will need to specify that name...

Delcare Function sha1_hash Lib "...." Alias "exported name from dumpbin"

(....) As ....

--
Tom Shelton
MVP [Visual Basic]

[Prashant Bhuptani]

Thanks a lot Tom and everyone else for your help.

So after doing a dumpin /exports on the dll I used the exported function
names and declared it in my VB code.
And hence it works now. So there was definitely no .DEF file used for the
functions.

Thanks again.

regards,
-Prashant

"Tom Shelton" <to*@mtogden.com> wrote in message
news:u$**************@TK2MSFTNGP10.phx.gbl...

In article <u9*************@tk2msftngp13.phx.gbl>, Prashant Bhuptani

wrote:

Hi Herfried,

I have a test code in VC++ which calls the exported methods of these dlls. These methods are declared in the header file as follows:

__declspec(dllexport) int sha1_hash(const unsigned char ci[],unsigned char co[]);
__declspec(dllexport) int aes_enc(const unsigned char ci[],char co[]);

However, I don't have the code which is used to create the dll.
So as of now I am not sure how the .def file is created, but if that helps in solving this problem, I can definitely find out.

Thanks,

Regards,
-Prashant

do a dumpbin /exports on the dll to see the exported names of the
functions. More then likely, they are not sha1_enc and aes_enc. There
is generally type information appended to the names (I don't remember
the exact characters any more). The point is, if there is no .DEF file
for the functions, the names actually get changed by the compiler. To
use them from VB.NET, you will need to specify that name...

Delcare Function sha1_hash Lib "...." Alias "exported name from dumpbin"

(....) As ....

--
Tom Shelton
MVP [Visual Basic]