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#### 10.2.2 Identifiers

An `IDENTIFIER_NODE` represents a slightly more general concept than the standard C or C++ concept of identifier. In particular, an `IDENTIFIER_NODE` may contain a ‘`$`’, or other extraordinary characters.

There are never two distinct `IDENTIFIER_NODE`s representing the same identifier. Therefore, you may use pointer equality to compare `IDENTIFIER_NODE`s, rather than using a routine like `strcmp`. Use `get_identifier` to obtain the unique `IDENTIFIER_NODE` for a supplied string.

You can use the following macros to access identifiers:

`IDENTIFIER_POINTER`

  The string represented by the identifier, represented as a `char*`. This string is always `NUL`-terminated, and contains no embedded `NUL` characters.

`IDENTIFIER_LENGTH`

  The length of the string returned by `IDENTIFIER_POINTER`, not including the trailing `NUL`. This value of `IDENTIFIER_LENGTH (x)` is always the same as `strlen (IDENTIFIER_POINTER (x))`.

`IDENTIFIER_OPNAME_P`

  This predicate holds if the identifier represents the name of an overloaded operator. In this case, you should not depend on the contents of either the `IDENTIFIER_POINTER` or the `IDENTIFIER_LENGTH`.

`IDENTIFIER_TYPENAME_P`

  This predicate holds if the identifier represents the name of a user-defined conversion operator. In this case, the `TREE_TYPE` of the `IDENTIFIER_NODE` holds the type to which the conversion operator converts.