英文:
Why are there empty spaces among stack memory allocated in C?
问题
The code you provided appears to be in C or C++. It seems that you are experiencing non-sequential memory allocation with some areas filled with cc cc cc cc. The presence of these spaces is likely due to how memory allocation and initialization work in your program. The cc cc cc cc values are often used to represent uninitialized memory or padding.
The reason for non-sequential memory allocation and the presence of these spaces can be attributed to various factors, including compiler optimizations, alignment requirements, and the specific memory allocation strategy used by your system.
To understand the exact reasons for this behavior, you may need to delve into the compiler settings, optimization options, and the memory allocation strategy of your development environment (Microsoft Visual Studio 2022 in this case). It's also possible that the compiler is introducing padding for alignment purposes, which is a common practice to ensure efficient memory access.
If you want to investigate further, you may consider examining compiler documentation or consulting with experts familiar with memory management and compiler internals.
英文:
cf. Environment: Microsoft Visual Studio 2022 17.5
// main.c
int main() {
int a = 0x12345, b = 0x67890;
int arr[5] = { 0x1234, 0x2345, 0x3456, 0x4567, 0x5678 };
return 0;
}
If I execute code above,<br>
and when I check my memory allocated with debugger,<br>
result is as follows.
0x0000002FC3EFF9F4 45 23 01 00 E#..
0x0000002FC3EFF9F8 cc cc cc cc ????
0x0000002FC3EFF9FC cc cc cc cc ????
0x0000002FC3EFFA00 cc cc cc cc ????
0x0000002FC3EFFA04 cc cc cc cc ????
0x0000002FC3EFFA08 cc cc cc cc ????
0x0000002FC3EFFA0C cc cc cc cc ????
0x0000002FC3EFFA10 cc cc cc cc ????
0x0000002FC3EFFA14 90 78 06 00 ?x..
0x0000002FC3EFFA18 cc cc cc cc ????
0x0000002FC3EFFA1C cc cc cc cc ????
0x0000002FC3EFFA20 cc cc cc cc ????
0x0000002FC3EFFA24 cc cc cc cc ????
0x0000002FC3EFFA28 cc cc cc cc ????
0x0000002FC3EFFA2C cc cc cc cc ????
0x0000002FC3EFFA30 cc cc cc cc ????
0x0000002FC3EFFA34 cc cc cc cc ????
0x0000002FC3EFFA38 34 12 00 00 4...
0x0000002FC3EFFA3C 45 23 00 00 E#..
0x0000002FC3EFFA40 56 34 00 00 V4..
0x0000002FC3EFFA44 67 45 00 00 gE..
0x0000002FC3EFFA48 78 56 00 00 xV..
What I see is that memory is NOT allocated sequentially<br>
and there exist spaces(?) which are not allocated.<br>
I mean, cc cc cc cc area.<br>
At first sight it seems not necessary. I wonder why these spaces exist.<br>
答案1
得分: 3
这主要是因为VC默认实现了缓冲区溢出保护。使用/GS-命令行开关并再次检查。
英文:
This is mainly because VC implements buffer overflow protection by default. Use /GS- command line switch and check again.
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