What is meaning of "[=]" in cpp

Question

Please check this code below:

NodeScheduleLambda(this, 0.01f, [=]
{
    this->removeFromParentAndCleanup(true);
});

In that what is the meaning of "[=]" this. Can any one help me.Thank you...

Answer 1

A lambda is an unnamed/anonymous function that is useful in programming due to it's short snippets of code.

lambda function in C++ defined like this

[]() { }

[] is the capture list, () the argument list and {} the function body.

The capture list defines what from the outside of the lambda should be available inside the function body and how. It can be either:

• a value: [x]
• a reference [&x]
• any variable currently in scope by reference [&]
• same as third type, but by value [=]

You're passing a lamda function as third argument using fourth capture list.

NodeScheduleLambda(this, 0.01f, [=]{ this->removeFromParentAndCleanup(true); });