C++ 与 Dll 通信出错

Question

我当前的项目有 2 个 dll，一个称为 Engine，另一个称为 Graphics。引擎链接到图形。然后是带有两者链接的主程序，但使用引擎。

在一些函数中是这样的:

typedef const char* ce_safechar;
AssimpIntegration::GetData(ce_safechar pFile, ...

此错误弹出:_pFirstBlock == pHead，就在我退出函数之后。

我见过很多不同的问题，似乎都指向字符串。

我怎样才能避免这种行为？

完整功能(如果需要):

FMESH_DATA AssimpIntegration::GetData(ce_safechar pFile, bool convLeftHanded, int maxSM)
{
    // Create an instance of the Importer class
    Assimp::Importer importer;
    // And have it read the given file with some example post processing
    // Usually - if speed is not the most important aspect for you - you'll 
    // probably to request more post processing than we do in this example.

    int cls = 0x0;
    if (convLeftHanded)
        cls = aiProcess_ConvertToLeftHanded;

    const aiScene* scene = importer.ReadFile( pFile, aiProcess_GenNormals | aiProcess_FindInstances | aiProcess_CalcTangentSpace | cls | aiProcess_Triangulate  );

    // If the import failed, report it
    if (!scene)
    {
        char* error = (char*)importer.GetErrorString();
        CE_ERROR(error, "Assimp Error");
    }

    // Now we can access the file's contents. 
    Group<MESH_STRUCT> Vertices;
    Group<DWORD> indices;

    //////////////////////////////////////////////////////////////////////////////////////////
    ///////////////////////////////////PROCESS MESH///////////////////////////////////////////
    //////////////////////////////////////////////////////////////////////////////////////////

    FMESH_DATA data;

    if (scene->HasAnimations())
    {
        aiAnimation *anim = scene->mAnimations[0];

        FOREACH(anim->mChannels[0]->mNumPositionKeys)
        {
            aiVector3D position = anim->mChannels[0]->mPositionKeys[i].mValue;

            CE_ANIMATIONKEY key;
            key.position = D3DXVECTOR3(position.x, position.y, position.z);

            data.Keys.push_back(key);
        }
    }

    D3DXVECTOR3 norms;
    float tanx, tany, tanz;
    float bitanx, bitany, bitanz;

    FOREACH (scene->mNumMeshes)
    {
        if (i >= maxSM)
            continue;

        aiMesh *mesh = scene->mMeshes[i];
        Vertices.group.clear();
        indices.group.clear(); //dafuck?

        if (mesh->HasPositions())
        {
            for (int v = 0; v != mesh->mNumVertices; v++)
            {
                norms = D3DXVECTOR3(0,0,0);
                if (mesh->HasNormals())
                    norms =  D3DXVECTOR3(mesh->mNormals[v].x,mesh->mNormals[v].y,mesh->mNormals[v].z);

                tanx = tany = tanz = 0;
                bitanx = bitany = bitanz = 0;

                if (mesh->HasTangentsAndBitangents())
                {
                    tanx = mesh->mTangents[v].x; tany = mesh->mTangents[v].y; tanz = mesh->mTangents[v].z;
                    bitanx = mesh->mBitangents[v].x; bitany = mesh->mBitangents[v].y; bitanz = mesh->mBitangents[v].z;
                }

                Vertices.push_back(MESH_STRUCT(
                    mesh->mVertices[v].x,
                    mesh->mVertices[v].y,
                    mesh->mVertices[v].z,
                    norms,
                    0,
                    0,
                    tanx, // TANGENTS
                    tany,
                    tanz
                ));

                for (int b = 0; b < mesh->mNumBones; b++)
                {
                    if (b > 4)
                        break;

                    float weight = 0.0f;

                    for ( int w = 0; w < mesh->mBones[b]->mNumWeights; w++)
                        if (mesh->mBones[b]->mWeights[w].mVertexId == v)
                            weight = mesh->mBones[b]->mWeights[w].mWeight;

                    Vertices.back().bWeight[b] = weight;
                }

                if (mesh->HasTextureCoords(0))
                {
                    Vertices.back().U = mesh->mTextureCoords[0][v].x;
                    Vertices.back().V = mesh->mTextureCoords[0][v].y;
                }
            }

            for (int f = 0; f != mesh->mNumFaces; f++)
            {
                for (int index = 0; index != mesh->mFaces[f].mNumIndices; index++)
                {
                    indices.push_back(mesh->mFaces[f].mIndices[index]);
                }
            }
        }

        data.meshData.push_back(Vertices);
        data.indices.push_back(indices);

        // Set the required textures
        const aiMaterial* pMaterial = scene->mMaterials[mesh->mMaterialIndex];

        if (pMaterial->GetTextureCount(aiTextureType_DIFFUSE) > 0) {
            aiString Path;

            if (pMaterial->GetTexture(aiTextureType_DIFFUSE, 0, &Path, NULL, NULL, NULL, NULL, NULL) == AI_SUCCESS) {
                std::string FullPath = Path.data;

                if (FullPath.find("\\") != string::npos)
                    FullPath = FullPath.substr(FullPath.find_last_of("\\")+1, FullPath.length() - (FullPath.length() - FullPath.find_last_of("\\")-1));
                else if (FullPath.find("/") != string::npos)
                    FullPath = FullPath.substr(FullPath.find_last_of("/")+1, FullPath.length() - FullPath.find_last_of("/")-1);

                string rFile = pFile;
                string spFile = std::string(pFile);

                if (spFile.find("\\") != string::npos)
                    rFile = spFile.substr(0, spFile.find_last_of("\\")+1);
                else
                    rFile = spFile.substr(0, spFile.find_last_of("/")+1);

                FullPath = rFile + FullPath;

                data.textures.push_back(FullPath);
            }
        }
        else
        {
            data.textures.push_back("");
        }
    }

    data.scene = scene;
    return data;
}

Answer 1

您正在使用 STL 对象作为您在 DLL 上导出的函数/方法的参数和/或返回类型。

示例:您返回 FMESH_DATA。这个类/结构内部有 STL 对象，我们可以通过以下行看到:

data.Keys.push_back(key);

这里的问题是:通过 DLL 导出或导入 STL 内容不是一个好主意。它要求 DLL 的调用者使用在 DLL 中创建的对象的相同 CRT。

但如果您真的想这样做，您可以将项目(所有项目)的运行时库更改为多线程 (/MD)。然后您将能够跨客户端和 DLL 安全地使用 STL。