const一词在字面上来源于常量constant,const对象在C/C++中是有不同解析的,如第二章所述,在C中常量表达式必须是编译期,运行期的不是常量表达式,因此C中的const不是常量表达式;但在C++中,由于去掉了编译期的限定,因此是常量表达式。 对于一个指向const对象的指针pointer to const T,由于把const视作常量表达式,常常...
// x is just a read-only pointer to something that may or may not be a constantvoidconstFunc(constint *x){// local_var is a true constantconstint local_var = 42;// Definitely undefined behaviour by C rules doubleIt((int*)&local_var);// Who knows if this is UB? doubleIt((...
const_cast中的未定义行为 上面的第一段程序,输出变量constant与*modefier的地址后... intmain() {constintconstant =26;constint* const_p = &constant;int* modifier = const_cast<int*>(const_p);*modifier =3; cout<<"constant:"<<constant<<"adderss:"<< &constant <<endl; cout<<"*modifier:"...
Pointer to Constant Data A pointer to const data does not allow modification of the data through the pointer. The declaration of const data merely requires that the const precede the *, so either of the following two declarations are valid. const type* variable; ...
The constant pointer to a variable is useful where you want a storage that can be changed in value but not moved in memory. Because the pointer will always point to the same memory location, because it is defined with const keyword, but the value at that memory location can...
pointer */const int const * c4;const int * const c5; /* Pointer is a constant pointer */...
Pointer to constant assigned address that does not contain a value expand all in page Description This defect occurs when a pointer to a constant (const int*, const char*, etc.) is assigned an address that does not yet contain a value. For instance: int x; const int * ptr = &x; Ri...
The warning was in the OP: assignment discards 'const' qualifier from pointer target type Your link helped. I had tried declaring as a pointer to constant data but then the two functions that use the pointer caused the same error. I had to change them to being passed a pointer to constan...
让我们从一个最简单、最明显的例子开始,以前认为这是一个const让 C 代码跑得更快的例子。首先,假设我们有如下两个函数声明: void func(int *x); void constFunc(const int *x); 然后假设我们如下两份代码: void byArg(int *x) { printf("%d\n", *x); ...
A pointer to a constant is declared as :const int *ptr(the location of 'const' makes the pointer 'ptr' as a pointer to constant. Is an array a const pointer? yes, the array name isa constant pointer tothe first element of the array, and a constant cannot be change. An array name...