I begin to use clang to replace gcc. But when I delete[] pointers, it gives warning. But when I change, the warning disappears. Why and how to deal with that?
int *a = new int[1];
int *b = new int[1];
delete[] a, b;
a.cpp:7:17: warning: expression result unused [-Wunused-value]
delete[] a, b;
int *a = new int[1];
int *b = new int[1];
delete[] a;
delete[] b;
no warning.
delete[] a, b;
is parsed as:
(delete[] a), (b);
Which you can really think of as:
delete[] a;
b;
In which case it is pretty clear that you're not doing much with b.
If you use -Wall, gcc will also warn on this since atleast 2007 (gcc 4.1.2):
<source>: In function 'int main()':
<source>:4:18: warning: right operand of comma operator has no effect [-Wunused-value]
4 | delete[] a, b;
| ^
Compiler returned: 0
delete[](a, b) Is this correct?
(a, b) is equivalent to b, because of the comma operator.
deletein a destructor - onedeleteper destructor. If you have two things that need to be deleted, you use two members managing one each. And often you don't need to write thatdeleteyourself. E.g.std::vector<int>manages thedelete[]for you.