David David - 1 year ago 59
C++ Question

Is there a way to write a lambda expression inside an IF with everything captured?

It's my understanding that if I use the syntax [&] in a lambda expression, then my lambda expression has access to surrounding variables and parameters of the function.

Therefore, I tried to write the following (simplified) code

if ( [&]()
bool b = false;
return b;
// Do something in TRUE part of if statement

but I get the error "Value of type 'lambda at...' is not contextually convertible to 'bool'

Would appreciate some insight into this issue.

Many thanks,

Answer Source

You need to call the lambda you're constructing. It will not be called implicitly.

if ([&]() { /*...*/ return b; }()) {
    //                         ^^ call the lambda
    // ...
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