unmanaged pointer to managed array

[MR]

I am new to VS.C++ and am having a hard time when i have to share data
between managed and unmanaged code.
For example, I need to read binary data from a file and then call an non-CLR
dll function passing the data that was read as a void*
below is a snippet of the code that i have written in an attempt to do this.
I tried __pin but that is no longer supported in VS.2005.

is there a better way than reading into the array as I did?
How do you do this?
thanks for your help
m


struct UnmanagedValues // create a struct to hold all nonManaged values.
{
void * buffer;
} unManagedValues ;
array<wchar_t>^ charBuffer = r->ReadChars(buff erSize); // read the data
into a managed array.
unManagedValues .buffer = &charBuffer; //but now I need to set the address of
the array as a void*. of course this line generates an error

[William DePalo [MVP VC++]]

Re: unmanaged pointer to managed array

"MR" <comconix@newsg roup.nospam> wrote in message
news:uzLv30okFH A.3316@TK2MSFTN GP14.phx.gbl...[color=blue]
>I am new to VS.C++ and am having a hard time when i have to share data
> between managed and unmanaged code.[/color]

You can use the wrapper template gcroot that appears in <vcclr.h>.
Essentially it gets you a handle to an allocation on the garbage collected
heap, and through some template magic allows you to "use" the handle as a
pointer in native code.

Details here:

http://msdn.microsoft.com/library/de...sSpec_16_3.asp

http://msdn.microsoft.com/msdnmag/issues/05/04/C/

Regards,
Will

[adebaene@club-internet.fr]

Re: unmanaged pointer to managed array



MR a écrit :[color=blue]
> I am new to VS.C++ and am having a hard time when i have to share data
> between managed and unmanaged code.
> For example, I need to read binary data from a file and then call an non-CLR
> dll function passing the data that was read as a void*
> below is a snippet of the code that i have written in an attempt to do this.
> I tried __pin but that is no longer supported in VS.2005.[/color]

You should use the new equivalent : cli::pin_ptr

[color=blue]
>
> is there a better way than reading into the array as I did?
> How do you do this?
> thanks for your help
> m
>
>
> struct UnmanagedValues // create a struct to hold all nonManaged values.
> {
> void * buffer;
> } unManagedValues ;
> array<wchar_t>^ charBuffer = r->ReadChars(buff erSize); // read the data
> into a managed array.
> unManagedValues .buffer = &charBuffer; //but now I need to set the address of
> the array as a void*. of course this line generates an error[/color]

use :
cli::pin_ptr<wc har_t> ptr= &charBuffer[0];
void* ptr2=ptr;
unManagedValues .buffer=ptr2;

Arnaud
MVP - VC

[Norman Diamond]

Re: unmanaged pointer to managed array

See:

http://weblogs.asp.net/kennykerr/archive/2005/07/12/419102.aspx

and a few other postings before and after that.

"MR" <comconix@newsg roup.nospam> wrote in message
news:uzLv30okFH A.3316@TK2MSFTN GP14.phx.gbl...[color=blue]
>I am new to VS.C++ and am having a hard time when i have to share data
> between managed and unmanaged code.
> For example, I need to read binary data from a file and then call an
> non-CLR
> dll function passing the data that was read as a void*
> below is a snippet of the code that i have written in an attempt to do
> this.
> I tried __pin but that is no longer supported in VS.2005.
>
> is there a better way than reading into the array as I did?
> How do you do this?
> thanks for your help
> m
>
>
> struct UnmanagedValues // create a struct to hold all nonManaged values.
> {
> void * buffer;
> } unManagedValues ;
> array<wchar_t>^ charBuffer = r->ReadChars(buff erSize); // read the data
> into a managed array.
> unManagedValues .buffer = &charBuffer; //but now I need to set the address
> of
> the array as a void*. of course this line generates an error
>
>
>[/color]

[Nishant Sivakumar]

Re: unmanaged pointer to managed array

See : http://www.voidnish.com/articles/Sho...e=cppcliarrays

There's a section titled : Direct manipulation of CLI arrays using native
pointers.

It may help.

--
Regards,
Nish [VC++ MVP]

http://www.voidnish.com

http://blog.voidnish.com

"MR" <comconix@newsg roup.nospam> wrote in message
news:uzLv30okFH A.3316@TK2MSFTN GP14.phx.gbl...[color=blue]
>I am new to VS.C++ and am having a hard time when i have to share data
> between managed and unmanaged code.
> For example, I need to read binary data from a file and then call an
> non-CLR
> dll function passing the data that was read as a void*
> below is a snippet of the code that i have written in an attempt to do
> this.
> I tried __pin but that is no longer supported in VS.2005.
>
> is there a better way than reading into the array as I did?
> How do you do this?
> thanks for your help
> m
>
>
> struct UnmanagedValues // create a struct to hold all nonManaged values.
> {
> void * buffer;
> } unManagedValues ;
> array<wchar_t>^ charBuffer = r->ReadChars(buff erSize); // read the data
> into a managed array.
> unManagedValues .buffer = &charBuffer; //but now I need to set the address
> of
> the array as a void*. of course this line generates an error
>
>
>[/color]