public static member function
<ios> <iostream>
Get new index for extensible array [static]
Returns a new index value to be used with member functions in the internal extensible array.
The internal extensible array is a general-purpose array of objects of type long (if accessed with member iword) or void* (if accessed with member pword).
This is a static member function.
返回值
A new index that can be used with either member iword or member pword.
数据竞争
Concurrently calling this function may introduce data races.
异常安全
Strong guarantee: if an exception is thrown, there are no changes in any stream.