Whats the correct C# datatype (or marshalling function or something) to use
when you're importing a function that has a signature similar to
char* FuncA(char c[])
?
Assuming you know that both the parameter for the function and the return
value are c-style strings?
Thanks in advance!
Tim
6  5896 
just so you know, what i'm trying is
[DllImport("MyDll.dll", EntryPoint="FuncA")]
private static extern IntPtr FuncA([MarshalAs(UnmanagedType.LPStr)] string
ParamA);
as per something i saw a little bit below in the Interop NG.. but i'm
getting a NullReferenceException when i make the calls to that function and
i'm wondering if its because of how i'm declaring it.
"Tim Mulholland" <Ti***********@nospamaddress.com> wrote in message
news:%2****************@TK2MSFTNGP11.phx.gbl... Whats the correct C# datatype (or marshalling function or something) to
use when you're importing a function that has a signature similar to
char* FuncA(char c[])
?
Assuming you know that both the parameter for the function and the return
value are c-style strings?
Thanks in advance!
Tim
I was able to get something similar to work by using StringBuilder:
... FuncA( StringBuilder string ParamA ) ;
It seems that the DllImport's default char set is ANSI so StringBuilder
marshals the parameter correctly. Also, my C function was declared
as CDECL and I had to specify the calling convention in the DllImport statement.
Ted
"Tim Mulholland" <Ti***********@nospamaddress.com> wrote in message news:<uB**************@tk2msftngp13.phx.gbl>... just so you know, what i'm trying is
[DllImport("MyDll.dll", EntryPoint="FuncA")]
private static extern IntPtr FuncA([MarshalAs(UnmanagedType.LPStr)] string
ParamA);
as per something i saw a little bit below in the Interop NG.. but i'm
getting a NullReferenceException when i make the calls to that function and
i'm wondering if its because of how i'm declaring it.
"Tim Mulholland" <Ti***********@nospamaddress.com> wrote in message
news:%2****************@TK2MSFTNGP11.phx.gbl... Whats the correct C# datatype (or marshalling function or something) to
use when you're importing a function that has a signature similar to
char* FuncA(char c[])
?
Assuming you know that both the parameter for the function and the return
value are c-style strings?
Thanks in advance!
Tim
It was your post i was referring to, so thanks for responding.
What do you mena you had to specify the calling convention in the DllImport
statement?
I'm still very stumped about why i get an exception when i don't debug the
unmanaged code, but no exception when i do...
"Ted Sung" <te**@intex.com> wrote in message
news:86**************************@posting.google.c om... I was able to get something similar to work by using StringBuilder:
.. FuncA( StringBuilder string ParamA ) ;
It seems that the DllImport's default char set is ANSI so StringBuilder
marshals the parameter correctly. Also, my C function was declared
as CDECL and I had to specify the calling convention in the DllImport
statement.
Ted
"Tim Mulholland" <Ti***********@nospamaddress.com> wrote in message
news:<uB**************@tk2msftngp13.phx.gbl>... just so you know, what i'm trying is
[DllImport("MyDll.dll", EntryPoint="FuncA")]
private static extern IntPtr FuncA([MarshalAs(UnmanagedType.LPStr)]
string ParamA);
as per something i saw a little bit below in the Interop NG.. but i'm
getting a NullReferenceException when i make the calls to that function
and i'm wondering if its because of how i'm declaring it.
"Tim Mulholland" <Ti***********@nospamaddress.com> wrote in message
news:%2****************@TK2MSFTNGP11.phx.gbl... Whats the correct C# datatype (or marshalling function or something)
to use when you're importing a function that has a signature similar to
char* FuncA(char c[])
?
Assuming you know that both the parameter for the function and the
return value are c-style strings?
Thanks in advance!
Tim
n/m, i found what the CallingConvention thing was. i declare mine with
__declspec(dllexport)
which one should i be using? They all seem to do the same thing (throw that
exception)
"Tim Mulholland" <Ti***********@nospamaddress.com> wrote in message
news:%2****************@TK2MSFTNGP10.phx.gbl... It was your post i was referring to, so thanks for responding.
What do you mena you had to specify the calling convention in the
DllImport statement?
I'm still very stumped about why i get an exception when i don't debug the
unmanaged code, but no exception when i do...
"Ted Sung" <te**@intex.com> wrote in message
news:86**************************@posting.google.c om... I was able to get something similar to work by using StringBuilder:
.. FuncA( StringBuilder string ParamA ) ;
It seems that the DllImport's default char set is ANSI so StringBuilder
marshals the parameter correctly. Also, my C function was declared
as CDECL and I had to specify the calling convention in the DllImport statement.
Ted
"Tim Mulholland" <Ti***********@nospamaddress.com> wrote in message
news:<uB**************@tk2msftngp13.phx.gbl>... just so you know, what i'm trying is
[DllImport("MyDll.dll", EntryPoint="FuncA")]
private static extern IntPtr FuncA([MarshalAs(UnmanagedType.LPStr)] string ParamA);
as per something i saw a little bit below in the Interop NG.. but i'm
getting a NullReferenceException when i make the calls to that
function and i'm wondering if its because of how i'm declaring it.
"Tim Mulholland" <Ti***********@nospamaddress.com> wrote in message
news:%2****************@TK2MSFTNGP11.phx.gbl...
> Whats the correct C# datatype (or marshalling function or something) to use
> when you're importing a function that has a signature similar to
>
> char* FuncA(char c[])
>
> ?
>
> Assuming you know that both the parameter for the function and the return > value are c-style strings?
>
> Thanks in advance!
>
> Tim
>
>
Tim, n/m, i found what the CallingConvention thing was. i declare mine with
__declspec(dllexport)
which one should i be using?
__declspec(dllexport) indicates that the function is to be exported,
it doesn't specify the calling convention. You use __stdcall, __cdecl
etc for that. The default is probably cdecl unless you cahnged it with
some compiler option.
Mattias
--
Mattias Sjögren [MVP] mattias @ mvps.org http://www.msjogren.net/dotnet/ | http://www.dotnetinterop.com
Please reply only to the newsgroup.
Tim, n/m, i found what the CallingConvention thing was. i declare mine with
__declspec(dllexport)
which one should i be using?
__declspec(dllexport) indicates that the function is to be exported,
it doesn't specify the calling convention. You use __stdcall, __cdecl
etc for that. The default is probably cdecl unless you cahnged it with
some compiler option.
Mattias
--
Mattias Sjögren [MVP] mattias @ mvps.org http://www.msjogren.net/dotnet/ | http://www.dotnetinterop.com
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