Also, pass-by-reference inherently requires a dereferencing operation, which can produce noticeable overhead in some operations, typically those used with these basic value types, like mathematics.
12.
Using the value of a variable when the name is in context but the variable is uninitialized is analogous to dereferencing ( accessing the value of ) a wild pointer, as it is undefined.
13.
Function compute _ sum in turn invokes one of the two functions indirectly by dereferencing its function pointer argument funcp multiple times, adding together the values that the invoked function returns and returning the resulting sum.
14.
Internal storage is usually more efficient, because there is a space cost for the references and dynamic allocation metadata, and a time cost associated with dereferencing a reference and with allocating the memory for the smaller objects.
15.
As an analogy, a page number in a book's index could be considered a pointer to the corresponding page; dereferencing such a pointer would be done by flipping to the page with the given page number.
16.
This system serves two purposes : it provides a substrate on which language-specific exception handling can be implemented, and it is how the kernel notifies applications of exceptional conditions such as dereferencing an invalid pointer or stack overflow.
17.
:Also, many languages explicitly allow for constructs that have undefined behaviour ( in C, e . g . comparing two arbitrary pointers, or the order of execution between sequence points, or, IIRC, dereferencing the NULL pointer ).
18.
This is because by using the dereferencing ampersand only one word ( typically 4 bytes on a 32 bit machine, 8 bytes on a 64 bit machine ) is required to be passed into the function, namely the memory location to the variable.
19.
For example, in x86-real mode, the address 0000 : 0000 is readable and usually writable, hence dereferencing the null pointer is a perfectly valid but typically unwanted action that may lead to undefined but non-crashing behaviour in the application.
20.
Use of bound information makes it possible for a compiler to generate code that performs bounds checking, i . e . that tests if a pointer's value lies within the bounds prior to dereferencing the pointer or modifying the value of the pointer.
