#selfdoubt

Question

What will happen if we dereference a dangling pointer?

will it lead to a segmentation fault(core dumped) or an invalid pointer error?

Answer 1

After freeing up a pointer variable if we are trying to de reference that, it gives error based on the platform. Suppose we have a code snippet like this:

int a=10,*p;

p = &a;

free(p);

*p = 20;

p is a dangling pointer right.

Now this code can primarily give two kinds of error but the kind of error depends totally on the platform and implementation.(Both the errors mentioned refers to the same Error Type. The error names are different based on the platform/implementation).

1. In case of UNIX based it will give Segmentation Fault( Core Dumped).
2. For rest of them it usually gives ILLEGAL MEMORY ACCESS.

Again the error is totally dependent on the platform.

Comments

The dangling pointer errors can be avoided by initializing the pointer to the NULL value. If we assign the NULL value to the pointer, then the pointer will not point to the de-allocated memory. Assigning NULL value to the pointer means that the pointer is not pointing to any memory location.

source:javaTpoint

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Thanks a lot for clarifying @robinofautumn, I knew it wrong. I will update the answer. 

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Thanks a lot to you too for helping me out.