In computing, a null pointer (sometimes shortened to nullptr or null) or null reference is a value saved for indicating that the pointer or reference does...

pointer be explicitly initialized to the null pointer value, which is traditionally specified in C with the standardized macro NULL: int *ptr = NULL;...

often occur because of errors in pointer use, particularly in C dynamic memory allocation. Dereferencing a null pointer, which results in undefined behavior...

representation. Null device, a virtual file that discards data written to it, on Unix systems /dev/null Null pointer or reference (sometimes written NULL, nil,...

implemented as null-terminated character arrays. Low-level access to computer memory is possible by converting machine addresses to pointers. Procedures...

system is able to detect run-time references to null pointers, a solution to the above is to assign 0 (null) to dp immediately before the inner block is...

following limits on programs: NULL checks are inserted to prevent segmentation faults Pointer arithmetic is limited Pointers must be initialized before use...

null pointer to his design of the ALGOL W language and called it a "mistake": I call it my billion-dollar mistake. It was the invention of the null reference...

never again be used, no code will try to access the null pointer, and because the pointer is null, its memory is not deleted when it goes out of scope...

no appropriate object available. A null reference is impossible in standard-conforming C++. A null Animal* pointer is possible, and could be useful as...

often ubiquitously used in C: NULL (expands to (void*)0, used prior to the introduction of nullptr to represent a null pointer) NDEBUG (a macro meaning "no-debug"...

unusable. This means that, for example, a pointer to 0 is never a valid pointer and can be used as a special null pointer value. Unlike the previously mentioned...

= NULL; // initialize invalid links to nil. if (head == NULL) { head = temp; // If the linked list is empty (i.e., the head node pointer is a null pointer)...

bugs; Swift has features addressing some common programming errors like null pointer dereferencing and provides syntactic sugar to help avoid the pyramid...

software documentation, the null character is often represented with the text NUL (or NULL although that may mean the null pointer). In Unicode, there is a...

not be null. Rust instead uses Option for this purpose: Some(T) indicates that a value is present, and None is analogous to the null pointer. Option...

object-oriented programming languages when one of the objects may be a null pointer. Most modern object-oriented programming languages use a coding style...

instance, creating a pointer with a null value and then attempting to use it is perfectly acceptable in C, leading to null-pointer errors. In contrast...

expression for rejecting all available candidates None, the keyword for the null pointer in Python Nones (disambiguation) Nothing (disambiguation) Zero (disambiguation)...

result of applying the unary * operator on a null pointer. Whether an exception is thrown for other null reference arguments is implementation-dependent...

might return a null pointer and it is good programming practice to check for this: int *array = malloc(10 * sizeof(int)); if (array == NULL) { fprintf(stderr...

can automatically detect such an invalid access (e.g. for the null value: a null pointer dereference error). This supports in analyzing the actual reason...

pointers, A null pointer type with only one value, null, indicating an exceptional condition. Unfortunately, C compilers do not verify that the null case...

termination of the code that made the invalid reference. A null pointer is usually represented as a pointer to address 0 in the address space; many operating systems...

from the creation of such a reference. In Rust, dereferencing a null pointer (std::ptr::null()) in an unsafe block results in undefined behaviour, which usually...

pointers that can be NULL require the user to check the pointer before using it and require specific code to handle the case when the object pointer is...

Windows actually make the zero page inaccessible to trap uses of null pointers. Such pointer values may legitimately indicate uninitialized values or sentinel...

C and C++, 0 represents the null pointer. As with Boolean values, the C standard library includes a macro definition NULL whose use is encouraged. Other...

destructor of an RAII object may lead to unexpected results, Null pointer dereference – A null pointer dereference will often cause an exception or program termination...

arithmetic types) or a null pointer (for pointer types). Implementations of C typically represent zero values and null pointer values using a bit pattern...