C++结构体内存分配问题

最新推荐文章于 2024-09-18 22:42:36 发布

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最新推荐文章于 2024-09-18 22:42:36 发布

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文章标签： c/c++

原文链接：http://www.cnblogs.com/pngcui/p/11180788.html

博客记录了在C/C++中动态申请DisplayInfo空间时遇到的问题。对distancePicInfo赋值操作时运行报错，提示引用非法地址，判断为内存申请失败。修改结构体声明后问题解决，后续将进一步研究。

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=========20190713 update================

结构体信息如下

struct picInfo{
    std::string path;
    unsigned int width;
    unsigned int height;
    unsigned int extra;    
};

struct areaPos{
    unsigned int width;
    unsigned int height;  
};

struct DisplayInfo{
    picInfo carPicInfo;
    unsigned int distancePicNum;
    picInfo* distancePicInfo;
    unsigned int frontRadarNum;
    unsigned int rightRadarNum;
    unsigned int rearRadarNum;
    unsigned int leftRadarNum;
    unsigned long distanceScale;
    areaPos envAreaPos;
    areaPos videoAreaPos;
};

目前需要动态申请一个DisplayInfo空间

使用如下方式申请内存

distancePicInfo = (picInfo* )malloc(10*sizeof(picInfo));

然后对distancePicInfo进行赋值操作

    for(auto && info:distInfoNode){
       distancePicInfo[distPicCnt].path= distInfo.path;
       distancePicInfo[distPicCnt].width= distInfo.width;
       distancePicInfo[distPicCnt].height= distInfo.height;
       distancePicInfo[distPicCnt].extra= distInfo.extra;
       distPicCnt++;    
    }

运行报错了，说引用了非法地址，可以得出申请内存肯定失败了的结论

修改结构体声明如下，即可解决

struct picInfo{
    const char* path;
    unsigned int width;
    unsigned int height;
    unsigned int extra;    
};

struct areaPos{
    unsigned int width;
    unsigned int height;  
};

struct DisplayInfo{
    picInfo carPicInfo;
    unsigned int distancePicNum;
    picInfo* distancePicInfo;
    unsigned int frontRadarNum;
    unsigned int rightRadarNum;
    unsigned int rearRadarNum;
    unsigned int leftRadarNum;
    unsigned long distanceScale;
    areaPos envAreaPos;
    areaPos videoAreaPos;
};