[thread.thread.id] (original) (raw)
32 Concurrency support library [thread]
32.4 Threads [thread.threads]
32.4.3 Class thread [thread.thread.class]
32.4.3.2 Class thread::id [thread.thread.id]
namespace std { class thread::id { public: id() noexcept;};bool operator==(thread::id x, thread::id y) noexcept; strong_ordering operator<=>(thread::id x, thread::id y) noexcept;template<class charT, class traits> basic_ostream<charT, traits>& operator<<(basic_ostream<charT, traits>& out, thread::id id);template<class charT> struct formatter<thread::id, charT>;template<class T> struct hash;template<> struct hashthread::id\;}
An object of type thread::id provides a unique identifier for each thread of execution and a single distinct value for all threadobjects that do not represent a thread of execution ([thread.thread.class]).
Each thread of execution has an associated thread::id object that is not equal to thethread::id object of any other thread of execution and that is not equal to the thread::id object of any thread object that does not represent threads of execution.
The text representation for the character type charT of an object of type thread::idis an unspecified sequence of charT such that, for two objects of type thread::id x and y, if x == y is true, the thread::id objects have the same text representation, and if x != y is true, the thread::id objects have distinct text representations.
thread::id is a trivially copyable class ([class.prop]).
The library may reuse the value of a thread::id of a terminated thread that can no longer be joined.
[Note 1:
Relational operators allow thread::id objects to be used as keys in associative containers.
— _end note_]
Postconditions: The constructed object does not represent a thread of execution.
bool operator==(thread::id x, thread::id y) noexcept;
Returns: true only if x and y represent the same thread of execution or neither x nor y represents a thread of execution.
strong_ordering operator<=>(thread::id x, thread::id y) noexcept;
Let P(x, y) be an unspecified total ordering over thread::idas described in [alg.sorting].
Returns: strong_ordering::less if P(x, y) is true.
Otherwise, strong_ordering::greaterif P(y, x) is true.
Otherwise, strong_ordering::equal.
template<class charT, class traits> basic_ostream<charT, traits>& operator<<(basic_ostream<charT, traits>& out, thread::id id);
Effects: Inserts the text representation for charT of id intoout.
template<class charT> struct formatter<thread::id, charT>;
formatter<thread::id, charT> interprets _format-spec_as a thread-id-format-spec.
The syntax of format specifications is as follows:
thread-id-format-spec :
fill-and-align width
[Note 2:
The productions fill-and-align and _width_are described in [format.string.std].
— _end note_]
If the align option is omitted it defaults to >.
A thread::id object is formatted by writing its text representation for charT to the output with additional padding and adjustments as specified by the format specifiers.
template<> struct hash<thread::id>;