It's also wrong. If the compiler inlines e.g. std::sort, it doesn't matter whether the comparator is a lambda or a pointer to a function: The compiler knows wha

It's also wrong. If the compiler inlines e.g. std::sort, it doesn't matter whether the comparator is a lambda or a pointer to a function: The compiler knows what it is and can inline it as well. The only exception is when the function is defined in a different compilation unit. Then the compiler has no access to its definition and thus cannot inline it into std::sort. The "C++ with lambda is faster than C with function" comes from C's qsort function that takes a function pointer to a comparator and is not inlined by the compiler. This can result in it being slower than std::sort. BTW since lambdas without capture decay to function pointers, you can pass such a lambda to qsort.