使用sscanf指向float [3]的指针,获取异常

时间:2011-12-21 09:45:15

标签: c++ exception pointers nullpointerexception scanf

编辑:好的,因为我之前太模糊了继承人SSCCE:

typedef float vector[3]

int mainLoaderFunc() {

    char* memory = NULL;
    size_t size = loadFile(fileName, &memory); // load model file into memory, this works, tested and true

    // create vector arrays
    vector *vertexArray = NULL;         
    vector *normalArray = NULL;         
    vector *textureArray = NULL;        

    loadArrays(size, memory, &vertexArray, &normalArray, &textureArray);

    // do other stuff with arrays

}

void loadArrays(size_t size, char *memory, vector **vertexArray, vector **normalArray, vector **textureArray) {

    int numVerts = 0; 
    int numNormals = 0;  
    int numTextures = 0;  

    char* p = memory;           // pointer to start of memory
    char* e = memory + size;    // pointer to end of memory

    // count verts, normals, textures for memory allocation
    while (p != e) {
        if (memcmp(p, "vn", 2) == 0) {
            numNormals++;
        } else if (memcmp(p, "vt", 2) == 0) { 
            numTextures++;
        } else if (memcmp(p, "v",  1) == 0) {
            numVerts++;
        } 
        while (*p++ != (char) 0x0A);
    }

    // allocate memory for vector arrays
    *vertexArray        = new vector[numVerts];
    *normalArray        = new vector[numNormals];
    *textureArray       = new vector[numTextures];


    int vertexIndex = 0;
    int normalIndex = 0;
    int textureIndex = 0;  //*** IF BREAK POINT HERE: NO EXCEPTION

    // load data from memory into arrays
    while (p != e) {

        if (memcmp(p, "vn", 2) == 0) {
            sscanf(p, "vn %f %f %f", normalArray[normalIndex][0], normalArray[normalIndex][1], normalArray[normalIndex][2]);
            normalIndex++;
        } else if (memcmp(p, "vt", 2) == 0) {
            sscanf(p, "vt %f %f", textureArray[textureIndex][0], textureArray[textureIndex][1]);
            textureIndex++;
        } else if (memcmp(p, "v", 1) == 0) {
            sscanf(p, "v %f %f %f", vertexArray[vertexIndex][0], vertexArray[vertexIndex][1], vertexArray[vertexIndex][2]);
            vertexIndex++;
        } 
        while (*p++ != (char) 0x0A);
    }

}

一旦代码命中sscanf部分,我就会得到异常,我已经尝试过放置&和* infront数组但是我得到了一个例外。

2 个答案:

答案 0 :(得分:3)

我猜你必须将地址传递给sscanf

sscanf(myMemChunk, "%f %f %f", &myVector[i][0], &myVector[i][1], &myVector[i][2]);

答案 1 :(得分:0)

sscanf在使用float *时需要%fvertexArrayfloat ***vertexArray[i]float **vertexArray[i][j]float*。但是,这不是您想要的,因为vertexArray是指向vertex数组的指针,因此您希望这样做:

&(*vertexArray)[i][j]

这样可以让您正确float *传递给sscanf