Dynamic initialization of a non-local variable with static storage duration is unordered if the variable is an implicitly or explicitly instantiated specialization, is partially-ordered if the variable is an inline variable that is not an implicitly or explicitly instantiated specialization, and otherwise is ordered. [ Note: An explicitly specialized non-inline static data member or variable template specialization has ordered initialization. — end note ]
Dynamic initialization of non-local variables V and W with static storage duration are ordered as follows:
If V and W have ordered initialization and V is defined before W within a single translation unit, the initialization of V is sequenced before the initialization of W.
If V has partially-ordered initialization, W does not have unordered initialization, and V is defined before W in every translation unit in which W is defined, then
if the program starts a thread ([intro.multithread]) other than the main thread ([basic.start.main]), the initialization of V strongly happens before the initialization of W;
otherwise, the initialization of V is sequenced before the initialization of W.
Otherwise, if the program starts a thread other than the main thread before either V or W is initialized, it is unspecified in which threads the initializations of V and W occur; the initializations are unsequenced if they occur in the same thread.
Otherwise, the initializations of V and W are indeterminately sequenced.
[ Note: This definition permits initialization of a sequence of ordered variables concurrently with another sequence. — end note ]
It is implementation-defined whether the dynamic initialization of a non-local non-inline variable with static storage duration is sequenced before the first statement of main or is deferred. If it is deferred, it strongly happens before any non-initialization odr-use of any non-inline function or non-inline variable defined in the same translation unit as the variable to be initialized.36 It is implementation-defined in which threads and at which points in the program such deferred dynamic initialization occurs. [ Note: Such points should be chosen in a way that allows the programmer to avoid deadlocks. — end note ] [ Example:
#include "a.h"
#include "b.h"
B b;
A::A(){
b.Use();
}
#include "a.h"
A a;
#include "a.h"
#include "b.h"
extern A a;
extern B b;
int main() {
a.Use();
b.Use();
}
It is implementation-defined whether either a or b is initialized before main is entered or whether the initializations are delayed until a is first odr-used in main. In particular, if a is initialized before main is entered, it is not guaranteed that b will be initialized before it is odr-used by the initialization of a, that is, before A::A is called. If, however, a is initialized at some point after the first statement of main, b will be initialized prior to its use in A::A. — end example ]
It is implementation-defined whether the dynamic initialization of a non-local inline variable with static storage duration is sequenced before the first statement of main or is deferred. If it is deferred, it strongly happens before any non-initialization odr-use of that variable. It is implementation-defined in which threads and at which points in the program such deferred dynamic initialization occurs.
It is implementation-defined whether the dynamic initialization of a non-local non-inline variable with thread storage duration is sequenced before the first statement of the initial function of a thread or is deferred. If it is deferred, the initialization associated with the entity for thread t is sequenced before the first non-initialization odr-use by t of any non-inline variable with thread storage duration defined in the same translation unit as the variable to be initialized. It is implementation-defined in which threads and at which points in the program such deferred dynamic initialization occurs.
If the initialization of a non-local variable with static or thread storage duration exits via an exception, std::terminate is called.
RetroSearch is an open source project built by @garambo | Open a GitHub Issue
Search and Browse the WWW like it's 1997 | Search results from DuckDuckGo
HTML:
3.2
| Encoding:
UTF-8
| Version:
0.7.4