1.9 KiB
libucontext
libucontext is a library which provides the ucontext.h C API. Unlike other implementations,
it faithfully follows the kernel process ABI when doing context swaps.
Notably, when combined with gcompat, it provides a fully compatible implementation of the ucontext
functions that are ABI compatible with glibc.
Since version 0.13, for some architectures, you can deploy to bare metal using newlib via the
FREESTANDING=yes make option. Systems which use a syscall cannot work this way. The table
below shows which architecture ports have been adapted to build with FREESTANDING=yes.
supported architectures
Adding support for new architectures is easy, but you need to know assembly language to do it.
| Architecture | Works on musl | Syscall | Supports FREESTANDING |
|---|---|---|---|
| aarch64 | ✓ | ||
| arm | ✓ | ||
| m68k | ✓ | ✓ | |
| mips | ✓ | ||
| mips64 | ✓ | ||
| ppc | ✓ | ✓ | |
| ppc64 | ✓ | ✓ | |
| riscv64 | ✓ | ||
| s390x | ✓ | ||
| x86 | ✓ | ✓ | |
| x86_64 | ✓ | ✓ |
building
libucontext uses a simple makefile build system. You should define ARCH= at build time, otherwise
the build system will attempt to guess using uname -m.
$ make ARCH=x86_64
$ make ARCH=x86_64 check
$ make ARCH=x86_64 DESTDIR=out install