elibc — Standard C Library for Elyz

Minimal C library for the Elyz OS, based on musl's organisational principles but adapted to Elyz's capability-based, syscall-less architecture.

Structure

elibc/
├── arch/               # Architecture-specific code
│   ├── generic/        # Fallback implementation & abstract interfaces
│   │   ├── kcall.h          #  Kernel-call abstraction (no syscalls in Elyz)
│   │   ├── startup_info.h   #  Process-startup description
│   │   └── bits/            #  Type-size definitions
│   └── x86_64/         # x86_64 port
│       ├── kcall.h           #  Kernel-call placeholder (ABI TBD)
│       ├── startup_info.h    #  x86_64 startup layout (ABI TBD)
│       ├── atomic_arch.h     #  Locked cmpxchg / atomic ops
│       └── bits/
├── include/            # Public headers (POSIX-like API)
├── src/                # Source implementations
│   ├── internal/       #  Libc state, errno, bump allocator (temporary)
│   ├── string/         #  Pure-C string ops (memcpy, strlen, etc.)
│   ├── stdio/          #  (reserved)
│   └── stdlib/         #  atoi, etc.
├── crt/                # C runtime entry point
├── Makefile
└── configure

Key differences from a traditional libc (glibc/musl)

Traditional (Linux)	Elyz / elibc
syscall/int 0x80	Capability invocation → PM Actor messaging
brk/sbrk	ELYZ_OP_ALLOCATE via elyz_kcall
_exit syscall	ELYZ_OP_EXIT via kcall
errno via TLS	__errno_location (plain global for now)

Porting to a new arch

1. Create arch/<name>/ with:
   • kcall.h — kernel-call mechanism
   • startup_info.h — process-startup layout
   • arch.mak — arch-specific compiler/linker flags
   • bits/alltypes.h.in — type sizes
   • atomic_arch.h — atomic ops (optional, fallback exists)
2. Add detection in configure
3. Build: ./configure && make

Building

./configure
make