pthread_rwlock_t implementation is missing try-lock functions (IDFGH-7685)

[Spacechild1]

ESP-IDF has recently added support for pthread_rwlock_t (32e3444), but strangely the try-lock functions pthread_wrlock_tryrdlock and pthread_wrlock_trywrlock are missing... I'm wondering why they have been omitted?

[0xjakob]

@Spacechild1

I'm wondering why they have been omitted?

They simply haven't been implemented. The original feature request came from the Rust-community who needed only the simple functionality. I'll take a look at the code within the next few days to see if the implementation would be easy.

[Spacechild1]

Thanks!

to see if the implementation would be easy.

They are pretty easy to implement: instead of waiting on the condition variable, you would just unlock the resource mutex and return EBUSY. (And don't touch waiting_writers.) I can also make a PR if necessary.

[svenstaro]

Has there been any progress on this? I think this functionality would be pretty neat to have. Speaking from a Rust perspective, it's actually required to make full use of the tracing ecosystem.

[elotom]

I also encountered this problem. It would be nice to have this for the Rust ecosystem.

[0xjakob]

The try-lock functions have been merged into master. Feel free to take a look.

[svenstaro]

Looks like e7312cc is still not in any release. What's the policy here? What future release would this be contained in?

[0xjakob]

Hi @svenstaro, it has been merged to master. This means it will go into the next release (v5.2), as well as all the following releases.