核心转储，但gdb无法找到确切位置

Question

Lets say i have an array A[10] and some other variables

And i am initializing it as

for(int i=0;i<20;i++) //intentionally 20
    A[i]=0;

so when you run this , it will initialize the array without any error and access is also possible but the gdb gives core dump on some other place (In my case, it was showing memory for other variable as changed)
Why it is not giving core dump during initialization of array?

Answer 1

IN c/c++ you have no protection for running out of bounds of the array, the crash happens as soon as you access memory that does not belong to the process. so as long as you go out of bounds and only write over your own memory on stack or in heap like other variables... the program will not crash, but the other variables will get changed, and if you change a pointer by this this might cause a future crash since the pointer then will point at some random memory address

Answer 2

There is no out of bounds error checking for PODs such as raw arrays during compile time, only during run time. You are invoking undefined behaviour . That being said prefer std::vector or std::array to raw (C-style) arrays in C++.