error: anachronistic old-style base class initializer [-fpermissive]

Question

I have this constructor which give an error on compilation :-

Time::Time(short y,short m,short d,short h,short mi,short s):
        (*this).y(y);
        (*this).m(m);
        (*this).d(d);
        (*this).h(h);
        (*this).mi(mi);
        (*this).s(s);   {};

here is full error:-

Time.cpp: In constructor ‘Time::Time(short int, short int, short int, short int, short int, short int)’:
Time.cpp:22:2: error: anachronistic old-style base class initializer [-fpermissive]
  (*this).y(y);
  ^
Time.cpp:21:61: error: unnamed initializer for ‘Time’, which has no base classes
 Time::Time(short y,short m,short d,short h,short mi,short s):
                                                             ^
Time.cpp:22:9: error: expected ‘{’ before ‘.’ token
  (*this).y(y);
         ^
Time.cpp: At global scope:
Time.cpp:22:9: error: expected unqualified-id before ‘.’ token
Time.cpp:23:4: error: expected unqualified-id before ‘this’
  (*this).m(m);
    ^~~~
Time.cpp:23:4: error: expected ‘)’ before ‘this’
Time.cpp:24:4: error: expected unqualified-id before ‘this’
  (*this).d(d);
    ^~~~
Time.cpp:24:4: error: expected ‘)’ before ‘this’
Time.cpp:25:4: error: expected unqualified-id before ‘this’
  (*this).h(h);
    ^~~~
Time.cpp:25:4: error: expected ‘)’ before ‘this’
Time.cpp:26:4: error: expected unqualified-id before ‘this’
  (*this).mi(mi);
    ^~~~
Time.cpp:26:4: error: expected ‘)’ before ‘this’
Time.cpp:27:4: error: expected unqualified-id before ‘this’
  (*this).s(s);  {};
    ^~~~
Time.cpp:27:4: error: expected ‘)’ before ‘this’
Time.cpp:27:17: error: expected unqualified-id before ‘{’ token
  (*this).s(s);  {};
                 ^

As a noob I have no idea what is going on. On googling ,I only find one stackoverflow link which also doesn't help.

similar question https://stackoverflow.com/questions/29422285/error-anachronistic-old-style-base-class-initializer — user2807083, Nov 14 '17 at 15:37

Bathsheba · Answer 1 · 2017-11-14T15:49:25.387

3

The way you have written it is not standard C++, hence the compiler diagnostic. Rewrite to the conventional syntax:

Time::Time(short y,short m,short d,short h,short mi,short s):
    y(y),
    m(m),
    // and so on, without a final comma
{
}

The compiler is able to disambiguate between a function parameter and a class member variable in this instance: y(y) initialises member y with parameter y.

Finally, are you sure you want signed types for time-like members?

edited Nov 14 '17 at 15:49

answered Nov 14 '17 at 15:33

Bathsheba

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I can’t compile with the `this->` syntax and the error message is even less helpful: [Compiler Explorer](https://godbolt.org/g/d2gSa2) – Daniel H Nov 14 '17 at 15:46
2

`this->` in constructor initializer list is simply illegal. Not "conventional". – AnT stands with Russia Nov 14 '17 at 15:47
@DanielH: Perhaps that is also anachronistic! (Actually, I've just tried it in the latest GCC and it is!) I've tinned it. – Bathsheba Nov 14 '17 at 15:47

Steve · Answer 2 · 2017-11-14T15:47:50.793

3

When initialising using an initializer list, you need to seperate it by ,, not ;. And ditch the this

Time::Time(short _y,short _m,short _d,short _h,short _mi,short _s):
    y(_y),
    m(_m),
    d(_d),
    h(_h),
    mi(_mi),
    s(_s)
{
}

I would agree that it's not a great error message, in this case.

edited Nov 14 '17 at 15:47

answered Nov 14 '17 at 15:34

Steve

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Your last edit is not needed, the scoping of `y(y)` is just fine. – rustyx Nov 14 '17 at 15:36
Did it for clarity rather than for the compiler :) – Steve Nov 14 '17 at 15:37

score 0 · Accepted Answer · answered Nov 14 '17 at 15:46

You are not allowed to use this to specify the class member you want to initialize in the constructor initializer list. Get rid of this entirely. It is not a matter of preference or style, it is just an error.

The error message about "old-style base class" is just a syntactic confusion: seeing nonsensical syntax in member initializer list the compiler gets confused.

error: anachronistic old-style base class initializer [-fpermissive]

3 Answers3