what does "typedef see below" mean in c++ standard library source code?

Question

When I am reading the source code of standard library, I always see usage of "see below" For example, in the source code of libcxx memory: http://llvm.org/svn/llvm-project/libcxx/trunk/include/memory, in the unique_ptr definition, a piece of code with "typedef see below pointer" the code looks like this:

typedef see below pointer;
typedef T element_type;
typedef D deleter_type;

// constructors
constexpr unique_ptr() noexcept;
explicit unique_ptr(pointer p) noexcept;
unique_ptr(pointer p, see below d1) noexcept;
unique_ptr(pointer p, see below d2) noexcept;
unique_ptr(unique_ptr&& u) noexcept;
unique_ptr(nullptr_t) noexcept : unique_ptr() { }
template <class U, class E>
    unique_ptr(unique_ptr<U, E>&& u) noexcept;
template <class U>
    unique_ptr(auto_ptr<U>&& u) noexcept;
...

I want to know what does this mean, and how it works? thanks!

That's not valid source code. It's part of the **specification** for `std::unique_ptr`, which is **text**, not compilable code. — Pete Becker, Dec 01 '16 at 13:46

score 3 · Answer 1 · answered Dec 01 '16 at 08:54

3

That's part of a comment. View the file with syntax highlighting next time.

answered Dec 01 '16 at 08:54

o11c

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score 0 · Answer 2 · answered Dec 01 '16 at 08:57

Unless you have some kind of contrivance like

#define see const; /*you are allowed to define something to a keyword*/
struct below{};
typedef see below pointer;/*this will now compile*/

typedef see below pointer; is not syntactically valid. It's part of the documentation in the source code that you cite.

what does "typedef see below" mean in c++ standard library source code?

2 Answers2