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The first two of these, const and volatile, are also present in C++, and are the only type qualifiers in C++. Thus in C++ the term " cv -qualified type" (for c onst and v olatile) is often used for "qualified type", while the terms " c -qualified type" and " v -qualified type" are used when only one of the qualifiers is relevant.
For example, in C, int const x = 1; declares an object x of int const type – the const is part of the type, as if it were parsed "(int const) x" – while in Ada, X: constant INTEGER:= 1_ declares a constant (a kind of object) X of INTEGER type: the constant is part of the object, but not part of the type.
Even functions can be const in C++. The meaning here is that only a const function may be called for an object instantiated as const; a const function doesn't change any non-mutable data. C# has both a const and a readonly qualifier; its const is only for compile-time constants, while readonly can be used in constructors and other runtime ...
; The 'enter' instruction can also do something similar); sub esp, 12 : 'enter' instruction could do this for us; mov [ebp-4], 3 : or mov [esp+8], 3; mov [ebp-8], 2 : or mov [esp+4], 2; mov [ebp-12], 1 : or mov [esp], 1 push 3 push 2 push 1 call callee; call subroutine 'callee' add esp, 12; remove call arguments from frame add eax, 5; modify ...
In C and C++, volatile is a type qualifier, like const, and is a part of a type (e.g. the type of a variable or field). The behavior of the volatile keyword in C and C++ is sometimes given in terms of suppressing optimizations of an optimizing compiler: 1- don't remove existing volatile reads and writes, 2- don't add new volatile reads and writes, and 3- don't reorder volatile reads and writes.
In 1989, C++ 2.0 was released, followed by the updated second edition of The C++ Programming Language in 1991. [32] New features in 2.0 included multiple inheritance, abstract classes, static member functions, const member functions, and protected members. In 1990, The Annotated C++ Reference Manual was published. This work became the basis for ...
Using #pragma once allows the C preprocessor to include a header file when it is needed and to ignore an #include directive otherwise. This has the effect of altering the behavior of the C preprocessor itself, and allows programmers to express file dependencies in a simple fashion, obviating the need for manual management.
This can be understood as taking a null pointer of type structure st, and then obtaining the address of member m within said structure. While this implementation works correctly in many compilers, it has generated some debate regarding whether this is undefined behavior according to the C standard, [2] since it appears to involve a dereference of a null pointer (although, according to the ...