Different types of *
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What are rvalues, lvalues, xvalues, glvalues, and prvalues?
The standard states:
3.2 The this pointer
1 In the body of a non-static (9.3) member function,
the keyword this is a non-lvalue expression whose value is the address of the
object for which the function is called.
What is the difference between rvalue,lvalue, non-rvalue, non-lvalue?
How many types of such *values are there? I mean i heard there xvalues also.
Need to understand this badly. And how are these related to temporaries and lambdas?
Sorry if i sound repetitive, perplexed, oxymoron-ic and redundant.
An lvalue is something that can appear on the l eft-hand side of an assignment. An rvalue is something that can appear on the r ight-hand side of an assignment. this is a non-lvalue expression in the sense that you aren't allowed to assign to it: you can't say this = new Foo(); , for instance.
[EDITED to add: the above paragraph is wrong, though it may be a useful mnemonic and does reflect the origins of the term. See comments below. The references below, however, are correct.]
See section 3.10 of the standard, at least if the draft I'm looking at is representative. Section [basic.lval]. It begins: "Every expression is either an lvalue or an rvalue."
That's in the existing standard. C++0x seems likely to introduce: xvalues, glvalues, prvalues. See What are rvalues, lvalues, xvalues, glvalues, and prvalues? for more abuot this.
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