sysl.sys

The C declarations behind printing, reading, searching and the mathematics library live here and are declared nowhere else, so what a freestanding target has to replace is this module and only this module. That is the whole reason it exists as a module rather than as an extern beside each caller.

It is a leaf: it imports nothing from the rest of the library, and it gives the allocator up — declaring a C function reaches no heap, whatever that function goes on to do.

Index

UNSUPPORTED

Constants

UNSUPPORTED

const UNSUPPORTED: int = -38

The status a hook answers when the target cannot make that call at all – not a failure of the call, but the absence of one. It is the one value that means this in every *.sys module (sysl.fs.sys, sysl.io.sys, sysl.process.sys, sysl.net.sys, sysl.env.sys), on every platform.

The contract those modules share is a system call’s: zero or more is success, and a negative answer is the code of the failure negated, so -1 is EPERM. This is the one negative answer that is not a code of the host’s, which is why it is -38 and not the host’s own ENOSYS: that is 38 on Linux and 78 on macOS, and the contract has to mean one thing everywhere. A program answering a hook for a target that has no way to perform the call returns it:

@export("sysl_fs_chmod")
no_chmod(path: *u8, len: usize, mode: u32) -> int = sysl.sys.UNSUPPORTED

The caller hears “not supported on this target”.