Time To Get Rid Of errno

My problem is not so much with errno and short read()/write() calls. That behavior is maybe surprising, but it is well-defined, and it has been well-defined pretty much ever since there was such a thing as UNIX.

I have a completely different issue with "errno". The bulk of the time that I had to make raw system calls has been in extremely low-level code. When the code executes, I can't make much of a guarantee about the execution environment. Quite frequently, there is no such thing as an "errno" variable (e.g. because I just called clone(), and didn't set up thread local storage yet).

This means, I would need libinux to have zero dependencies on any libc code. No accesses to "errno", no accesses to thread local storage, no cancellation points, no locking, no calls to atfork handlers, nothing! But things get even more complicated than that. By default, the dynamic linker lazily resolves library functions. This means, whenever I make a call into libinux, there is a chance that the dynamic loader gets called and makes all sorts of calls that are incompatible with my particular requirements.

In other words, all of libinux would either need to be inline functions, or there needs to be a way to fully resolve its symbols on demand. It is quite possible that my needs are a little unusual, as I have been writing very low-level and Linux specific code. But that's probably something that people will end up wanting to use libinux for.

Other than that, yes, I am fully in favor of libinux giving easy and direct access to all Linux system calls. That feature is long overdue and would be very welcome. I also feel that having wrapper functions that make system calls easier to use is wonderful. I sometimes need the exact raw system calls; and when I do, I am OK with researching the idiosyncrasies of the kernel API and making sure I get things right. But most of the time, I don't need this much control and I actually appreciate having helpers that allow the compiler to make sure I don't do anything stupid.