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My understanding of the C standard is that is explicitly does not allow you to dereference NULL, even if you really want to know what is at memory address 0. Of
by gizmo686 11y ago
My understanding of the C standard is that is explicitly does not allow you to dereference NULL, even if you really want to know what is at memory address 0. Of course this behaviour is only undefined, so an implementation if free to let you do it if it wants to.
- Kristine1975 11y agoMinor nitpick: A NULL pointer need not point to memory address 0 (e.g. it could point to the highest possible address, or have a special "this is a NULL pointer" bit set). The C11 Standard does a little dance with "null pointer" and "null pointer constant" there, c.f. chapter 6.3.2.3: An integer constant expression with the value 0 [...] is called a null pointer constant. If a null pointer constant is converted to a pointer type, the resulting pointer, called a null pointer, is guaranteed to compare unequal to a pointer to any object or function.