An lvalue expression is an expression which has identity, but cannot be implicitly moved from. Among these are expressions that consist of a variable name, function name, expressions that are built-in dereference operator uses and expressions that refer to lvalue references.
The typical lvalue is simply a name, but lvalues can come in other flavors as well:
struct X { ... };
X x; // x is an lvalue
X* px = &x; // px is an lvalue
*px = X{}; // *px is also an lvalue, X{} is a prvalue
X* foo_ptr(); // foo_ptr() is a prvalue
X& foo_ref(); // foo_ref() is an lvalue
Additionally, while most literals (e.g. 4
, 'x'
, etc.) are prvalues, string literals are lvalues.