How do you check for an invalid pointer?

Question

My current code to the effect of:

if( objectPointer != NULL){
    delete objectPointer;
}

doesn't work because the pointers are getting set to invalid hex numbers by the compiler such as:

• 0xbaadf00d
• 0xdeadbeef

etc....

So what's the best way to check for an invalid pointer before trying to delete the object?

Answer 1

Always initialize your pointers to NULL (that is, 0). From http://www.lysator.liu.se/c/c-faq/c-1.html:

A null pointer is conceptually different from an uninitialized pointer. A null pointer is known not to point to any object; an uninitialized pointer might point anywhere.

Answer 2

You don't need to check for not-NULL when calling delete. It is explicitly defined to do nothing.

delete NULL; // this is allowed

Any correct code you are writing would not be affected by these weird values the compiler is putting into your uninitialised or already freed memory. It puts those values there in order to help you find bugs. Ergo, you have a bug.