Using std::bind with a lambda function

Question

The following code does not compile:

auto greater_than = [](const int a, const int b) { return a > b; };
auto is_adult = bind(&greater_than, placeholders::_1, 17);
cout << "Age 19 is adult = " << is_adult(19) << endl;

The is_adult call is giving a vague error:

error: no matching function for call to object of type 'std::_Bind<(lambda at main.cpp:62:23) *(std::_Placeholder<1>, int)>'

However, if I move the greater_than to be a global function then it works.

Why is that?

remove the &.

Chris Dodd
– Chris Dodd

2021-02-20 20:27:12 +00:00
Commented Feb 20, 2021 at 20:27 — Chris Dodd
– Chris Dodd, Commented Feb 20, 2021 at 20:27
just fyi: clang.llvm.org/extra/clang-tidy/checks/…

PiotrNycz
– PiotrNycz

2021-02-20 20:32:34 +00:00
Commented Feb 20, 2021 at 20:32 — PiotrNycz
– PiotrNycz, Commented Feb 20, 2021 at 20:32

HolyBlackCat · Accepted Answer · 2021-02-20 20:25:47Z

5

Remove the &. Even though pointers-to-functions are callable, pointers to objects with overloaded operator() are not.

answered Feb 20, 2021 at 20:25

HolyBlackCat

103k13 gold badges182 silver badges306 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Using std::bind with a lambda function

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related