tidy - readability-non-const-parameter — Extra Clang Tools 22.0.0git documentation (original) (raw)

The check finds function parameters of a pointer type that could be changed to point to a constant type instead.

When const is used properly, many mistakes can be avoided. Advantages when using const properly:

• prevent unintentional modification of data;
• get additional warnings such as using uninitialized data;
• make it easier for developers to see possible side effects.

This check is not strict about constness, it only warns when the constness will make the function interface safer.

// warning here; the declaration "const char *p" would make the function // interface safer. char f1(char *p) { return *p; }

// no warning; the declaration could be more const "const int * const p" but // that does not make the function interface safer. int f2(const int *p) { return *p; }

// no warning; making x const does not make the function interface safer int f3(int x) { return x; }

// no warning; Technically, *p can be const ("const struct S *p"). But making // *p const could be misleading. People might think that it's safe to pass // const data to this function. struct S { int *a; int *b; }; int f3(struct S *p) { *(p->a) = 0; }

// no warning; p is referenced by an lvalue. void f4(int *p) { int &x = *p; }