this post was submitted on 11 Apr 2024
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Linux is a family of open source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991 by Linus Torvalds. Linux is typically packaged in a Linux distribution (or distro for short).
Distributions include the Linux kernel and supporting system software and libraries, many of which are provided by the GNU Project. Many Linux distributions use the word "Linux" in their name, but the Free Software Foundation uses the name GNU/Linux to emphasize the importance of GNU software, causing some controversy.
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You have stderr to throw errors into. And the constants are just error codes, like HTTP error codes. Without it how computer would know if the program executed correctly.
stderr is useless if the syscall already returns a single integer only because of stupid C conventions.
You throw an exception like a gentleman. But C doesn't support them. So you need to abuse the return type to also indicate "success" as well as a potential value the caller wanted.
You don't need to.
Returnung structs, returning by pointer, signals, error flags, setjmp/longjmp, using cxa for exceptions(lol, now THIS is real abuse).
Exceptionss are bad coding, and what's abusive of using the full range of an integer? 0 success, everything else, error - check the API for details or call
strerror.Returning error codes in-band is the reason for a significant percentage of C bugs and security holes when the return value is used without checking. Something like Rust's Result type that forces you to distinguish the two cases is much better design here. And no, you are not working with a whole language ecosystem of "sufficiently disciplined programmers" so that nobody ever forgets to check a return value.
Not to mention that errno is just a very broken design in the times of modern thread and event systems, signals, interrupts and all kinds of other ways to produce race conditions and overwrite the errno value before it is checked.
errno is not shared between threads. Also:
There does not add more race conditions because signal handlers execute in one of regular threads. In single-threaded program signals are functions that can be called by OS at any point of execution, but they do not execute at same time with threads.
errno is bad programming.