C# to unmanaged C++

[MottetCCSF]

I have created 2 structures in my C# code :

        [StructLayoutAttribute(LayoutKind.Sequential, CharSet = CharSet.Ansi)]
        public class RollInformationCSharp
        {
            [MarshalAs(UnmanagedType.R8)]
            public double rollDiameter;
 
            [MarshalAs(UnmanagedType.R8)]
            public double initialRoughness;
 
            [MarshalAs(UnmanagedType.R8)]
            public double finalRoughness;
 
            [MarshalAs(UnmanagedType.R8)]
            public double accumulateCombination;
 
            [MarshalAs(UnmanagedType.R8)]
            public double critialRollLength;
 
            [MarshalAs(UnmanagedType.R8)]
            public double rolledLength;
 
            [MarshalAs(UnmanagedType.R8)]
            public double percentageLifeRoll;
 
            [MarshalAsAttribute(UnmanagedType.ByValTStr, SizeConst = 256)]
            public string rollName;
         };

and :

      [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)]
        public class MultiRollCSharp
        {
            [MarshalAs(UnmanagedType.I4)]
            public int nbRoll;
 
            public RollInformationCSharp[] tabRoll;
        }

In the C# code, i invoke a function of C++ dll :

        [DllImport("DLL_RaFTmodel.dll", CharSet = CharSet.Ansi)]
        public static extern IntPtr DLL_FlesCalculation(MultiRollCSharp multiRollInfo,
                                              CoilInformationCSharp coilInfo,
                                              RollInformationCSharp rollInfo,
                                              LimitsTypeCSharp LimitsSteel,
                                              LimitsTypeCSharp LimitsRegulation,
                                              LimitsTypeCSharp LimitsMachine,
                                              FTInputsCsharp forceTensionInfo,
                                              RaConstantsCSharp RaModelIn,
                                              FTWeightCsharp FTmodelIn,
                                              [In, MarshalAs(UnmanagedType.I4)] int strategy,
                                              [In, MarshalAs(UnmanagedType.I4)] int rollLifeMaximization,
                                              RaInputsCsharp RaDataIn,
                                              char Version,
                                              [In, MarshalAs(UnmanagedType.R4)] float errMax,
                                              [Out, MarshalAs(UnmanagedType.I4)] out int error);

In C++, I have also 2 structures :

struct RollInformation
{
    double rollDiameter;
    double initialRoughnessRoll;
    double finalRoughnessRoll;
    double accumulateCombination;
    double percentageLifeRoll;
    double criticalRollLength;
    double rolledLength;
    char rollName[256];
};

and

struct MultiRollInformation
{
    int nbRoll;
    RollInformation* tabRoll;
};

The function is also declared as follow :

extern EXPORTTOTEM_API 
MULTICURVETYPE* DLL_FlesCalculation( struct MultiRollInformation *multiRollInfo,                                     struct CoilInformation *coilInfo, 
             struct RollInformation *rollInfo,
             struct LimitsType *LimitsSteel,
             struct LimitsType *LimitsRegulation,
             struct LimitsType *LimitsMachine,
             struct FTInputs *forceTensionInfo,
             struct RaConstants *constRaIn,
             struct FTWeight *modelFTIn,
             int strategy,
             int rollLifeMaximization,
             struct RaInputs *dataRaIn,
                         char Version,
             float errMax,
             int &error);   

Example to fill the structure in C# :

            MultiRollCSharp multiRollInfo = new MultiRollCSharp();
            for(int i = 0; i < 5; i++)
            {
                RollInformationCSharp rollInfo1 = GetRollInformation();
                int taille = 0;
                if (multiRollInfo.tabRoll != null)
                    taille = multiRollInfo.tabRoll.Length;
 
                RollInformationCSharp[] tab = new RollInformationCSharp[taille +1];
                if (taille > 0)
                {
                    multiRollInfo.tabRoll.CopyTo(tab, 0);
                }
                tab[tab.Length-1] = rollInfo1;
                multiRollInfo.tabRoll = tab;
 
                multiRollInfo.nbRoll += 1;
            }

In debug mode, just before the call to the DLL, the both structures in C# are right (multiRollInfo and rollInfo)
.
In C++, the rollInfo is good. But the the multiroll info has 5 elements but there values are wrong .

What is wrong?
How can I correct this?

thank you very much for your help