C，Python，ctypes退出代码-1073741819（0xC0000005）

Question

C代码（DLL）

#include <math.h>
#include <wchar.h>
#include <stdlib.h>
struct Doc
{
    wchar_t path[512];
    int r;
    int g;
    int b;
};

struct Docs
{
    struct Doc docs[1000000];
};

struct Color
{
    int r;
    int g;
    int b;
};

float distance(int a, int b, int c, int d, int e, int f)
{
    return sqrt((a-b)*(a-b)+(c-d)*(c-d)+(e-f)*(e-f));
}

struct Doc main(long len, struct Color c, struct Docs ds)
{
    long near = 1000000;
    long l;
    struct Doc f_d;
    for (l = 0; l < len; l++){
        struct Doc d = ds.docs[l];
        float dist = distance(c.r, d.r, c.g, d.g, c.b, d.b);
        if (dist < near){
            near = dist;
            f_d = d;
        }
    }
    return f_d;
};

Python代码

class Doc(ctypes.Structure):
    _fields_ = [("path", ctypes.c_wchar_p),
                ("r", ctypes.c_int),
                ("g", ctypes.c_int),
                ("b", ctypes.c_int)]

class Docs(ctypes.Structure):
    _fields_ = [("docs", Doc * 1000000)]

class Color(ctypes.Structure):
    _fields_ = [("r", ctypes.c_int),
                ("g", ctypes.c_int),
                ("b", ctypes.c_int)]

structure = ctypes.CDLL('st.dll').main
structure.restype = Doc
structure.argstypes = (ctypes.c_long, Color(), Docs(),)

从python调用main函数后，它会退出，退出代码为-1073741819 exe执行后返回"Process finished with exit code -1073741819 (0xC0000005)"
我认为这是因为内存分配或类似的事情。