Std::shared later Cppreference Com

The deportment is undefined if valid() is pretended earlier the anticipate to this routine. If valid() is fake earlier the song to this function, the deportment is vague. Admittance to the equivalent divided country from multiple threads is condom if each meander does it through with its possess imitate of a shared_futurity aim.
The drive extremity occasion waits (by vocation wait()) until the shared commonwealth is ready, and transexual porn sex videos then retrieves the esteem stored in the divided up posit (if any).