What is a null macro?
What is the differtents between a null pointer and a null macro?
What is near, far and huge pointer?
How many bytes are occupied by them?
How would you obtain segment and offset addresses from a far address of a memory location?
NULL MACRO = (void *) 0Null pointer contains zeroth location chat *ptr = 0;you can use zero instead of NULL macro (I AM TALING ABOUT C). It will harm you.
NULL Macro is simply what is defined as 0 in a macro provided by the library
Null pointer is a pointer which has 0 or NULL value stored and points to nowhwere still it points to 0x00 i.e. the first memory location of the OS
Null pointer != Uninitialized pointer because an uninitialised pointer can point anywhere in the memory location ...but a NULL pointer surely points to no where(but still behind the scene we can say that it only points to 0x00). Never we can retrive a Null pointer location using th"&" operator..neither will malloc/calloc return NULL IF THERE IS SPACE IN THE MEMORY. NULL pointer is unique !!
RE: What is a null macro? What is the differtents between a null pointer and a null macro?What is near, far and huge pointer? How many bytes are occupied by them?How would you obtain segment and offset addresses from a far address of a memory location?
A null pointer should not be confused with an uninitialized pointer: a null pointer is guaranteed to compare unequal to any valid pointer, whereas depending on the language and implementation an uninitialized pointer might have either an indeterminate (random or meaningless) value or might be initialised to an initial constant (possibly but not necessarily NULL).
In C and C++ programming, two null pointers are guaranteed to compare equal; ANSI C guarantees that any NULL pointer will be equal to 0 in a comparison with an integer type.
