'HANDLE *' Error

[bhumithakker]

I am using a DLL function (complied in VC7), which takes a parameter
of 'HANDLE *' datatype.
The DLL developers recommend passing a HANDLE object using the
following syntax:

HANDLE obj =NULL;
func(&obj);

On successful execution of the code 'obj' is initialised to some
value.

This code works if used within VC++ MFC Application using VS2005.
But the same doesnt work in VC++ Windows Form Application using
VS2005.

In a VC++ Windows Form Application using VS2005, the compiler expects
the following syntax:

HANDLE obj =NULL;
func((HANDLE *)obj);

This compiles but gives a runtime error, and fails to initialise
'obj'.

What am I doing wrong? And how can I use the DLL function in a VC++
Windows Form Application using VS2005.

Thanks,
Bhumi

[Sheng Jiang[MVP]]

You are passing a null address to the function, and the function expects a
valida address to write to. You can use new to allocate memory on the native
heap, pass it to the dll to retrieve the new handle, and copy the handle
value to the managed heap.

--
Sheng Jiang
Microsoft MVP in VC++
<bh**********@gmail.comwrote in message
news:11*********************@z24g2000prh.googlegro ups.com...

I am using a DLL function (complied in VC7), which takes a parameter
of 'HANDLE *' datatype.
The DLL developers recommend passing a HANDLE object using the
following syntax:

HANDLE obj =NULL;
func(&obj);

On successful execution of the code 'obj' is initialised to some
value.

This code works if used within VC++ MFC Application using VS2005.
But the same doesnt work in VC++ Windows Form Application using
VS2005.

In a VC++ Windows Form Application using VS2005, the compiler expects
the following syntax:

HANDLE obj =NULL;
func((HANDLE *)obj);

This compiles but gives a runtime error, and fails to initialise
'obj'.

What am I doing wrong? And how can I use the DLL function in a VC++
Windows Form Application using VS2005.

Thanks,
Bhumi

[Bhumi]

On Oct 16, 1:00 am, "Sheng Jiang[MVP]"
<[e-mail]:

You are passing a null address to the function, and the function expects a
valida address to write to. You can use new to allocate memory on the native
heap, pass it to the dll to retrieve the new handle, and copy the handle
value to the managed heap.

--
Sheng Jiang
Microsoft MVP in VC++<[e-mail] in message

news:11*********************@z24g2000prh.googlegro ups.com...

I am using a DLL function (complied in VC7), which takes a parameter
of 'HANDLE *' datatype.
The DLL developers recommend passing a HANDLE object using the
following syntax:

HANDLE obj =NULL;
func(&obj);

On successful execution of the code 'obj' is initialised to some
value.

This code works if used within VC++ MFC Application using VS2005.
But the same doesnt work in VC++ Windows Form Application using
VS2005.

In a VC++ Windows Form Application using VS2005, the compiler expects
the following syntax:

HANDLE obj =NULL;
func((HANDLE *)obj);

This compiles but gives a runtime error, and fails to initialise
'obj'.

What am I doing wrong? And how can I use the DLL function in a VC++
Windows Form Application using VS2005.

Thanks,
Bhumi- Hide quoted text -

- Show quoted text -

Thanks Sheng. Got it to work now.

Thanks,
Bhumi

[Ben Voigt [C++ MVP]]

<bh**********@gmail.comwrote in message
news:11*********************@z24g2000prh.googlegro ups.com...

>I am using a DLL function (complied in VC7), which takes a parameter
of 'HANDLE *' datatype.
The DLL developers recommend passing a HANDLE object using the
following syntax:

HANDLE obj =NULL;
func(&obj);

On successful execution of the code 'obj' is initialised to some
value.

This code works if used within VC++ MFC Application using VS2005.
But the same doesnt work in VC++ Windows Form Application using
VS2005.

It should, because that is the correct version.

>
In a VC++ Windows Form Application using VS2005, the compiler expects
the following syntax:

HANDLE obj =NULL;
func((HANDLE *)obj);

This compiles but gives a runtime error, and fails to initialise
'obj'.

What am I doing wrong? And how can I use the DLL function in a VC++
Windows Form Application using VS2005.

Thanks,
Bhumi