llvm/llvm-project

Check the ordering of the *at syscalls

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#195620 opened on May 4, 2026

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good first issuelibc

Description

In our syscalls in LLVM libc, we often have clauses like:

#ifdef SYS_mkdir
#elif SYS_mkdirat
#endif

I want to check if we should be preferring the *at syscalls on systems that have both as I think they're newer and preferred.

Contributor guide

Tech stack
cpp
Domain
tooling
Issue type
research
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
C++LLVM libcsyscall interface
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
45
Research direction
Search the LLVM libc source tree for syscall selection patterns like `#ifdef SYS mkdir` followed by `#elif SYS mkdirat`. Determine if the *at variants are available on all target systems and if they should be used preferentially. Check existing comments or discussions in linked issues for consensus. No PRs linked yet.