C#'s REF or OUT in Managed C++

[Ryan Gregg]

I'm working on creating a wrapper for some old code we have in C++ so that
we can call it from a C# program. In C++ we have several functions defined
that use the following notation:

static long CalcCPL(double API60, double Temperature, double Pressure,
double& ComputationalCPL, double& PrintingCPL);

Where the double& arguments are output values from the function call. When
I compile these into a managed C++ class, and try to use it from inside a C#
program, I get the following message:

C:\Class1.cs(27): Argument '3': cannot convert from 'out double' to
'double*'
C:\Class1.cs(27): Argument '4': cannot convert from 'out double' to
'double*'
C:\Class1.cs(27): Argument '5': cannot convert from 'out short' to 'short*'

I've tried defining the function using the [Out] attribute or the [Ref]
attribute, but I get the same errors. Can someone help me figure out what
I'm doing wrong?

Thanks.

Ryan Gregg

[Mattias Sjögren]

Ryan,

static long CalcCPL(double API60, double Temperature, double Pressure,
double& ComputationalCPL, double& PrintingCPL);

To get a ref parameter you change it to

Double ComputationalCPL

or

double __gc & ComputationalCPL

To make it out, add the [Out] attribute.

Mattias

--
Mattias Sjögren [MVP] mattias @ mvps.org
http://www.msjogren.net/dotnet/ | http://www.dotnetinterop.com
Please reply only to the newsgroup.

[Ryan Gregg]

Thank you!! That solved my problem.

Ryan Gregg
"Mattias Sjögren" <ma********************@mvps.org> wrote in message
news:Oc**************@TK2MSFTNGP10.phx.gbl...

Ryan,

static long CalcCPL(double API60, double Temperature, double Pressure,
double& ComputationalCPL, double& PrintingCPL);

To get a ref parameter you change it to

Double ComputationalCPL

or

double __gc & ComputationalCPL

To make it out, add the [Out] attribute.

Mattias

--
Mattias Sjögren [MVP] mattias @ mvps.org
http://www.msjogren.net/dotnet/ | http://www.dotnetinterop.com
Please reply only to the newsgroup.