struct Context {
    enum Code next;
    struct Worker* worker;
    struct TaskManager* taskManager;
    int codeNum;
    __code (**code) (struct Context*);
    union Data **data;
    struct Meta **metaDataStart;
    struct Meta **metaData;
    void* heapStart;
    void* heap;
    long heapLimit;
    int dataNum;

    // task parameter
    int idgCount; //number of waiting dataGear
    int idg;
    int maxIdg;
    int odg;
    int maxOdg;
    int gpu; // GPU task
    struct Context* task;
    struct Element* taskList;
#ifdef USE_CUDAWorker
    int num_exec;
    CUmodule module;
    CUfunction function;
#endif
    /* multi dimension parameter */
    int iterate;
    struct Iterator* iterator;
};