Why doesn't my program crash when I write past the end of an array?

user_156437 0
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Why does the code below work without any crash @ runtime ?

And also the size is completely dependent on machine/platform/compiler!!. I can even give upto 200 in a 64-bit machine. how would a segmentation fault in main function get detected in the OS?

int main(int argc, char* argv[])
{
    int arr[3];
    arr[4] = 99;
}

Where does this buffer space come from? Is this the stack allocated to a process ?

callstack stack c
9 Answers

So apparently when you're asking the computer for a certain amount of bytes to allocate in memory, say: char array[10] it gives us a few extra bytes in order not to bump into segfault, however it's still not safe to use those, and trying to reach further memory will eventually cause the program to crash.

user_108164040
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