The this pointer is a keyword for C++ therfore there is no library needed to implement this. And do not forget this is a pointer! So you cannot do:

this.someMember();

As you access member functions or member variables from pointers using the arrow symbol -> :

this->someMember();

Other helpful links to the better understanding of the this pointer:

this pointer

Using the this pointer to access member data

Using the this pointer to differentiate between member data and parameters

this pointer cv-qualifiers

this pointer ref-qualifiers