_PyOS_SigintEvent() is needed for interruptible waiting on main thread

Bug report

Bug description:

Moved from https://github.com/python/cpython/pull/108605#issuecomment-2521215855

In https://github.com/python/cpython/pull/108605, _PyOS_SigintEvent was removed from the public headers.

TensorStore relies on that function here: https://github.com/google/tensorstore/blob/eda046b10158e7d82fdb0f23aeecdfdeb8ac5aa3/python/tensorstore/future.cc#L105 to enable synchronously blocking on the readiness of a custom Future type while allowing Ctrl+C to interrupt when running on the main thread.

The current workaround is to manually declare the function since the symbol is still available.

I'm not aware of a usable alternative. Since signal.set_wakeup_fd only allows a single fd to be set globally, it isn't usable from a library. The best alternative would probably be to poll by waking up every few hundred milliseconds.

CPython versions tested on:

3.13

Operating systems tested on:

No response

Iniziare esaminando CPython PR #108605 e l’uso di _PyOS_SigintEvent in python/tensorstore/future.cc di TensorStore, alla riga 105. Tracciare l’impatto della rimozione della dichiarazione dall’header pubblico sulle librerie di estensione e confrontare le alternative disponibili per il risveglio tramite segnali. Il lavoro sarà considerato completato quando sarà disponibile un modo supportato per consentire a una libreria di interrompere l’attesa sincrona nel thread principale, mantenendo il comportamento di Ctrl+C.