syscall - Cryo

import std::sys::syscall; · source

Two surfaces, gated by target

// Linux x86-64
type enum Syscall : i64 {
    read      = 0;
    write     = 1;
    open      = 2;
    close     = 3;
    stat      = 4;
    // ... the full <asm/unistd_64.h> table
}

![target(linux)] function sys_call0(num: Syscall) -> i64;
![target(linux)] function sys_call1(num: Syscall, a: i64) -> i64;
// ... through
![target(linux)] function sys_call6(num: Syscall, a: i64, b: i64, c: i64, d: i64, e: i64, f: i64) -> i64;

![target(linux)] function sys_read(fd: i32, buf: u8*, count: u64) -> i64;
![target(linux)] function sys_write(fd: i32, buf: u8*, count: u64) -> i64;
![target(linux)] function sys_open(path: u8*, flags: i32, mode: u32) -> i32;
![target(linux)] function sys_close(fd: i32) -> i32;
![target(linux)] function sys_mmap(addr: u8*, length: u64, prot: i32, flags: i32, fd: i32, offset: i64) -> u8*;
![target(linux)] function sys_fork() -> i32;
![target(linux)] function sys_execve(path: u8*, argv: u8**, envp: u8**) -> i32;
![target(linux)] function sys_gettid() -> i32;
![target(linux)] function sys_pidfd_open(pid: i32, flags: u32) -> i32;
![target(linux)] function sys_clone3(args: u8*, size: u64) -> i64;
![target(linux)] function sys_io_uring_setup(entries: u32, params: u8*) -> i32;
// ... ~120 typed wrappers

// Windows x86-64
type struct FILETIME { ... }
type struct SYSTEMTIME { ... }
type struct SECURITY_ATTRIBUTES { ... }
type struct OVERLAPPED { ... }
type struct STARTUPINFOA { ... }
type struct PROCESS_INFORMATION { ... }
type struct LARGE_INTEGER { ... }

![target(windows)] ![link("kernel32")]
extern "C" {
    function GetLastError() -> u32;
    function CreateFileA(...) -> void*;
    function VirtualAlloc(...) -> void*;
    // ... kernel32, user32, advapi32, ws2_32, ntdll
}

Two distinct surfaces live here, each gated by target so the other platform's symbols never reach the linker.

Linux x86-64 gets the full syscall number table as the Syscall enum, typed wrappers for the common cases (sys_read, sys_clone3, sys_io_uring_setup, and so on), and the generic sys_call0 through sys_call6 entry points that issue the raw syscall instruction via inline assembly. The typed wrappers return whatever the kernel returns — -errno on failure — with no normalisation beyond the cast to the natural return type.

Windows x86-64 gets the Win32 system surface — kernel32, user32, advapi32, ws2_32 — plus a small NT API surface from ntdll for programs that want to skip Win32. The handful of structs the calls need (FILETIME, STARTUPINFOA, PROCESS_INFORMATION, ...) are declared with their real layouts; the ![link(...)] attribute names the import library each block resolves against.

Constants have no link-time presence, so the syscall numbers and the Win32 constants are declared unconditionally. Only the extern "C" blocks and the typed wrappers that call into them carry ![target(...)] gates.

When to reach for this instead of `ffi::libc`

Reach for ffi::libc first. Its functions go through glibc's well-tested wrappers and are portable across Unix variants. Drop down to sys::syscall only when:

You need a syscall libc doesn't expose — gettid, pidfd_open, io_uring_setup, bpf, userfaultfd, clone3, the Landlock family.
You are writing a stub libc and want to avoid recursion.
You need bit-exact control over which syscall a code path issues: kernel fuzzing, eBPF tracers, sandbox enforcement.
You are on Windows and want the Win32 surface directly rather than through a libc personality.

ABI notes

The Linux numbers are the x86-64 ABI from <asm/unistd_64.h>. arm64, i386, and riscv64 use different numbers; a future per-arch split will gate that block.

The Windows bindings target the x64 ABI (the Microsoft x64 calling convention). x86 stdcall is not supported.

Constants

const CLONE_VM:                           u64 = 0x00000100;
const CLONE_FS:                           u64 = 0x00000200;
const CLONE_FILES:                        u64 = 0x00000400;
const CLONE_SIGHAND:                      u64 = 0x00000800;
const CLONE_PIDFD:                        u64 = 0x00001000;
const CLONE_PTRACE:                       u64 = 0x00002000;
const CLONE_VFORK:                        u64 = 0x00004000;
const CLONE_PARENT:                       u64 = 0x00008000;
const CLONE_THREAD:                       u64 = 0x00010000;
const CLONE_NEWNS:                        u64 = 0x00020000;
const CLONE_SYSVSEM:                      u64 = 0x00040000;
const CLONE_SETTLS:                       u64 = 0x00080000;
const CLONE_PARENT_SETTID:                u64 = 0x00100000;
const CLONE_CHILD_CLEARTID:               u64 = 0x00200000;
const CLONE_DETACHED:                     u64 = 0x00400000;
const CLONE_UNTRACED:                     u64 = 0x00800000;
const CLONE_CHILD_SETTID:                 u64 = 0x01000000;
const CLONE_NEWCGROUP:                    u64 = 0x02000000;
const CLONE_NEWUTS:                       u64 = 0x04000000;
const CLONE_NEWIPC:                       u64 = 0x08000000;
const CLONE_NEWUSER:                      u64 = 0x10000000;
const CLONE_NEWPID:                       u64 = 0x20000000;
const CLONE_NEWNET:                       u64 = 0x40000000;
const CLONE_IO:                           u64 = 0x80000000;
const FUTEX_WAIT:                         i32 = 0;
const FUTEX_WAKE:                         i32 = 1;
const FUTEX_FD:                           i32 = 2;
const FUTEX_REQUEUE:                      i32 = 3;
const FUTEX_CMP_REQUEUE:                  i32 = 4;
const FUTEX_WAKE_OP:                      i32 = 5;
const FUTEX_LOCK_PI:                      i32 = 6;
const FUTEX_UNLOCK_PI:                    i32 = 7;
const FUTEX_TRYLOCK_PI:                   i32 = 8;
const FUTEX_WAIT_BITSET:                  i32 = 9;
const FUTEX_WAKE_BITSET:                  i32 = 10;
const FUTEX_WAIT_REQUEUE_PI:              i32 = 11;
const FUTEX_CMP_REQUEUE_PI:               i32 = 12;
const FUTEX_PRIVATE_FLAG:                 i32 = 128;
const FUTEX_CLOCK_REALTIME:               i32 = 256;
const GRND_NONBLOCK:                      u32 = 1;
const GRND_RANDOM:                        u32 = 2;
const GRND_INSECURE:                      u32 = 4;
const PR_SET_PDEATHSIG:                   i32 = 1;
const PR_GET_PDEATHSIG:                   i32 = 2;
const PR_SET_DUMPABLE:                    i32 = 4;
const PR_GET_DUMPABLE:                    i32 = 3;
const PR_SET_NAME:                        i32 = 15;
const PR_GET_NAME:                        i32 = 16;
const PR_SET_SECCOMP:                     i32 = 22;
const PR_GET_SECCOMP:                     i32 = 21;
const PR_SET_NO_NEW_PRIVS:                i32 = 38;
const PR_GET_NO_NEW_PRIVS:                i32 = 39;
const SECCOMP_SET_MODE_STRICT:            u32 = 0;
const SECCOMP_SET_MODE_FILTER:            u32 = 1;
const SECCOMP_GET_ACTION_AVAIL:           u32 = 2;
const SECCOMP_GET_NOTIF_SIZES:            u32 = 3;
const PIDFD_NONBLOCK:                     u32 = 2048;
const INVALID_HANDLE_VALUE:               i64 = -1;
const NULL_HANDLE:                        u64 = 0;
const STD_INPUT_HANDLE:                   u32 = 4294967286;
const STD_OUTPUT_HANDLE:                  u32 = 4294967285;
const STD_ERROR_HANDLE:                   u32 = 4294967284;
const STARTF_USESTDHANDLES:               u32 = 0x100;
const HANDLE_FLAG_INHERIT:                u32 = 0x1;
const DUPLICATE_SAME_ACCESS:              u32 = 0x2;
const GENERIC_READ:                       u32 = 0x80000000;
const GENERIC_WRITE:                      u32 = 0x40000000;
const GENERIC_EXECUTE:                    u32 = 0x20000000;
const GENERIC_ALL:                        u32 = 0x10000000;
const FILE_SHARE_READ:                    u32 = 0x00000001;
const FILE_SHARE_WRITE:                   u32 = 0x00000002;
const FILE_SHARE_DELETE:                  u32 = 0x00000004;
const CREATE_NEW:                         u32 = 1;
const CREATE_ALWAYS:                      u32 = 2;
const OPEN_EXISTING:                      u32 = 3;
const OPEN_ALWAYS:                        u32 = 4;
const TRUNCATE_EXISTING:                  u32 = 5;
const FILE_ATTRIBUTE_READONLY:            u32 = 0x1;
const FILE_ATTRIBUTE_HIDDEN:              u32 = 0x2;
const FILE_ATTRIBUTE_SYSTEM:              u32 = 0x4;
const FILE_ATTRIBUTE_DIRECTORY:           u32 = 0x10;
const FILE_ATTRIBUTE_ARCHIVE:             u32 = 0x20;
const FILE_ATTRIBUTE_NORMAL:              u32 = 0x80;
const FILE_ATTRIBUTE_TEMPORARY:           u32 = 0x100;
const FILE_ATTRIBUTE_REPARSE_POINT:       u32 = 0x400;
const FILE_FLAG_WRITE_THROUGH:            u32 = 0x80000000;
const FILE_FLAG_OVERLAPPED:               u32 = 0x40000000;
const FILE_FLAG_NO_BUFFERING:             u32 = 0x20000000;
const FILE_FLAG_RANDOM_ACCESS:            u32 = 0x10000000;
const FILE_FLAG_SEQUENTIAL_SCAN:          u32 = 0x08000000;
const FILE_FLAG_DELETE_ON_CLOSE:          u32 = 0x04000000;
const FILE_FLAG_BACKUP_SEMANTICS:         u32 = 0x02000000;
const FILE_FLAG_OPEN_REPARSE_POINT:       u32 = 0x00200000;
const GetFileExInfoStandard:              u32 = 0;
const FILE_BEGIN:                         u32 = 0;
const FILE_CURRENT:                       u32 = 1;
const FILE_END:                           u32 = 2;
const MEM_COMMIT:                         u32 = 0x1000;
const MEM_RESERVE:                        u32 = 0x2000;
const MEM_DECOMMIT:                       u32 = 0x4000;
const MEM_RELEASE:                        u32 = 0x8000;
const MEM_RESET:                          u32 = 0x80000;
const MEM_RESET_UNDO:                     u32 = 0x1000000;
const MEM_LARGE_PAGES:                    u32 = 0x20000000;
const MEM_PHYSICAL:                       u32 = 0x400000;
const MEM_TOP_DOWN:                       u32 = 0x100000;
const PAGE_NOACCESS:                      u32 = 0x01;
const PAGE_READONLY:                      u32 = 0x02;
const PAGE_READWRITE:                     u32 = 0x04;
const PAGE_WRITECOPY:                     u32 = 0x08;
const PAGE_EXECUTE:                       u32 = 0x10;
const PAGE_EXECUTE_READ:                  u32 = 0x20;
const PAGE_EXECUTE_READWRITE:             u32 = 0x40;
const PAGE_EXECUTE_WRITECOPY:             u32 = 0x80;
const PAGE_GUARD:                         u32 = 0x100;
const PAGE_NOCACHE:                       u32 = 0x200;
const WAIT_OBJECT_0:                      u32 = 0;
const WAIT_ABANDONED_0:                   u32 = 0x80;
const WAIT_TIMEOUT:                       u32 = 0x102;
const WAIT_FAILED:                        u32 = 0xFFFFFFFF;
const INFINITE:                           u32 = 0xFFFFFFFF;
const HEAP_NO_SERIALIZE:                  u32 = 0x1;
const HEAP_GROWABLE:                      u32 = 0x2;
const HEAP_GENERATE_EXCEPTIONS:           u32 = 0x4;
const HEAP_ZERO_MEMORY:                   u32 = 0x8;
const HEAP_REALLOC_IN_PLACE_ONLY:         u32 = 0x10;
const CREATE_SUSPENDED:                   u32 = 0x4;
const DETACHED_PROCESS:                   u32 = 0x8;
const CREATE_NEW_CONSOLE:                 u32 = 0x10;
const CREATE_NEW_PROCESS_GROUP:           u32 = 0x200;
const CREATE_UNICODE_ENVIRONMENT:         u32 = 0x400;
const CREATE_BREAKAWAY_FROM_JOB:          u32 = 0x1000000;
const CREATE_NO_WINDOW:                   u32 = 0x8000000;
const ERROR_SUCCESS:                      u32 = 0;
const ERROR_FILE_NOT_FOUND:               u32 = 2;
const ERROR_PATH_NOT_FOUND:               u32 = 3;
const ERROR_ACCESS_DENIED:                u32 = 5;
const ERROR_INVALID_HANDLE:               u32 = 6;
const ERROR_NOT_ENOUGH_MEMORY:            u32 = 8;
const ERROR_BAD_FORMAT:                   u32 = 11;
const ERROR_INVALID_DATA:                 u32 = 13;
const ERROR_NO_MORE_FILES:                u32 = 18;
const ERROR_SHARING_VIOLATION:            u32 = 32;
const ERROR_HANDLE_EOF:                   u32 = 38;
const ERROR_NOT_SUPPORTED:                u32 = 50;
const ERROR_FILE_EXISTS:                  u32 = 80;
const ERROR_INVALID_PARAMETER:            u32 = 87;
const ERROR_BROKEN_PIPE:                  u32 = 109;
const ERROR_DISK_FULL:                    u32 = 112;
const ERROR_INSUFFICIENT_BUFFER:          u32 = 122;
const ERROR_INVALID_NAME:                 u32 = 123;
const ERROR_ALREADY_EXISTS:               u32 = 183;
const ERROR_NO_DATA:                      u32 = 232;
const ERROR_PIPE_BUSY:                    u32 = 231;
const ERROR_MORE_DATA:                    u32 = 234;
const ERROR_NO_MORE_ITEMS:                u32 = 259;
const ERROR_DIRECTORY:                    u32 = 267;
const ERROR_OPERATION_ABORTED:            u32 = 995;
const ERROR_IO_INCOMPLETE:                u32 = 996;
const ERROR_IO_PENDING:                   u32 = 997;
const ERROR_TIMEOUT:                      u32 = 1460;
const STATUS_SUCCESS:                     u32 = 0;
const STATUS_PENDING:                     u32 = 259;
const STATUS_BUFFER_OVERFLOW:             u32 = 0x80000005;
const STATUS_NO_MORE_FILES:               u32 = 0x80000006;
const STATUS_INVALID_HANDLE:              u32 = 0xC0000008;
const STATUS_INVALID_PARAMETER:           u32 = 0xC000000D;
const STATUS_END_OF_FILE:                 u32 = 0xC0000011;
const STATUS_ACCESS_DENIED:               u32 = 0xC0000022;
const FORMAT_MESSAGE_ALLOCATE_BUFFER:     u32 = 0x100;
const FORMAT_MESSAGE_IGNORE_INSERTS:      u32 = 0x200;
const FORMAT_MESSAGE_FROM_STRING:         u32 = 0x400;
const FORMAT_MESSAGE_FROM_HMODULE:        u32 = 0x800;
const FORMAT_MESSAGE_FROM_SYSTEM:         u32 = 0x1000;
const FORMAT_MESSAGE_ARGUMENT_ARRAY:      u32 = 0x2000;
const ENABLE_PROCESSED_INPUT:             u32 = 0x1;
const ENABLE_LINE_INPUT:                  u32 = 0x2;
const ENABLE_ECHO_INPUT:                  u32 = 0x4;
const ENABLE_WINDOW_INPUT:                u32 = 0x8;
const ENABLE_MOUSE_INPUT:                 u32 = 0x10;
const ENABLE_INSERT_MODE:                 u32 = 0x20;
const ENABLE_QUICK_EDIT_MODE:             u32 = 0x40;
const ENABLE_EXTENDED_FLAGS:              u32 = 0x80;
const ENABLE_PROCESSED_OUTPUT:            u32 = 0x1;
const ENABLE_WRAP_AT_EOL_OUTPUT:          u32 = 0x2;
const ENABLE_VIRTUAL_TERMINAL_PROCESSING: u32 = 0x4;
const ENABLE_VIRTUAL_TERMINAL_INPUT:      u32 = 0x200;
const CP_ACP:                             u32 = 0;
const CP_OEMCP:                           u32 = 1;
const CP_UTF7:                            u32 = 65000;
const CP_UTF8:                            u32 = 65001;
const MB_OK:                              u32 = 0;
const MB_OKCANCEL:                        u32 = 1;
const MB_ABORTRETRYIGNORE:                u32 = 2;
const MB_YESNOCANCEL:                     u32 = 3;
const MB_YESNO:                           u32 = 4;
const MB_RETRYCANCEL:                     u32 = 5;
const MB_ICONERROR:                       u32 = 0x10;
const MB_ICONWARNING:                     u32 = 0x30;
const MB_ICONINFORMATION:                 u32 = 0x40;
const IDOK:                               i32 = 1;
const IDCANCEL:                           i32 = 2;
const IDABORT:                            i32 = 3;
const IDRETRY:                            i32 = 4;
const IDIGNORE:                           i32 = 5;
const IDYES:                              i32 = 6;
const IDNO:                               i32 = 7;
const HKEY_CLASSES_ROOT:                  u64 = 0xFFFFFFFF80000000;
const HKEY_CURRENT_USER:                  u64 = 0xFFFFFFFF80000001;
const HKEY_LOCAL_MACHINE:                 u64 = 0xFFFFFFFF80000002;
const HKEY_USERS:                         u64 = 0xFFFFFFFF80000003;
const HKEY_CURRENT_CONFIG:                u64 = 0xFFFFFFFF80000005;
const KEY_QUERY_VALUE:                    u32 = 0x1;
const KEY_SET_VALUE:                      u32 = 0x2;
const KEY_CREATE_SUB_KEY:                 u32 = 0x4;
const KEY_ENUMERATE_SUB_KEYS:             u32 = 0x8;
const KEY_NOTIFY:                         u32 = 0x10;
const KEY_READ:                           u32 = 0x20019;
const KEY_WRITE:                          u32 = 0x20006;
const KEY_ALL_ACCESS:                     u32 = 0xF003F;
const REG_NONE:                           u32 = 0;
const REG_SZ:                             u32 = 1;
const REG_EXPAND_SZ:                      u32 = 2;
const REG_BINARY:                         u32 = 3;
const REG_DWORD:                          u32 = 4;
const REG_DWORD_BIG_ENDIAN:               u32 = 5;
const REG_MULTI_SZ:                       u32 = 7;
const REG_QWORD:                          u32 = 11;
const INVALID_SOCKET:                     u64 = 18446744073709551615;
const SOCKET_ERROR:                       i32 = -1;
const WSAEINTR:                           i32 = 10004;
const WSAEWOULDBLOCK:                     i32 = 10035;
const WSAEADDRINUSE:                      i32 = 10048;
const WSAECONNRESET:                      i32 = 10054;
const WSAECONNREFUSED:                    i32 = 10061;
const WSAETIMEDOUT:                       i32 = 10060;
const WSAECONNABORTED:                    i32 = 10053;
const WSAENOTCONN:                        i32 = 10057;
const FIONBIO:                            i32 = -2147195266;
const SOL_SOCKET:                         i32 = 65535;
const SO_ERROR:                           i32 = 4103;
const SO_CONNECT_TIME:                    i32 = 28684;
const SO_CONNECT_TIME_NEVER:              u32 = 0xFFFFFFFF;
const IOCTL_AFD_POLL:                     u32 = 0x00012024;
const AFD_POLL_RECEIVE:                   u32 = 0x0001;
const AFD_POLL_RECEIVE_EXPEDITED:         u32 = 0x0002;
const AFD_POLL_SEND:                      u32 = 0x0004;
const AFD_POLL_DISCONNECT:                u32 = 0x0008;
const AFD_POLL_ABORT:                     u32 = 0x0010;
const AFD_POLL_LOCAL_CLOSE:               u32 = 0x0020;
const AFD_POLL_ACCEPT:                    u32 = 0x0080;
const AFD_POLL_CONNECT_FAIL:              u32 = 0x0100;
const SIZEOF_IO_STATUS_BLOCK:             u64 = 16;
const SIZEOF_OVERLAPPED:                  u64 = 32;
const SIZEOF_AFD_POLL_INFO:               u64 = 32;
const SIZEOF_OBJECT_ATTRIBUTES:           u64 = 48;
const SIZEOF_UNICODE_STRING:              u64 = 16;
const SIZEOF_OVERLAPPED_ENTRY:            u64 = 32;
const SYNCHRONIZE:                        u32 = 0x00100000;
const FILE_SHARE_RW:                      u32 = 3;
const FILE_OPEN:                          u32 = 1;
const SIO_BASE_HANDLE:                    u32 = 0x48000022;
const IOCP_KICK_KEY:                      u64 = 1;

type struct Name { ... }
type enum Name { ... }
type trait Name { ... }
type union Name { ... }

Begins a type declaration; the keyword that follows says which kind. On its own, type Name = Existing; declares an alias.

language reference

type enum Name {
    Unit,
    Payload(T),
    Named { x: i32 },
}

An algebraic data type. Variants may be bare or carry a tuple or struct payload, and a match on an enum must cover every variant. Name::Variant names a variant; methods are added with implement enum Name { ... }.

language reference

type enum Syscall : i64 {
    read = 0;
    write = 1;
    open = 2;
    close = 3;
    stat = 4;
    fstat = 5;
    lstat = 6;
    poll = 7;
    lseek = 8;
    mmap = 9;
    // … 334 more
}

Linux x86_64 syscall identifier. Mutually exclusive: the kernel dispatches on the integer value in rax. Pass to syscall() or sys_callN(...); the i64 backing matches glibc's long syscall(long, ...) ABI exactly.

primitive i64

64-bit signed integer.

primitive type

Syscall::read = 0

Syscall::write = 1

Syscall::open = 2

Syscall::close = 3

Syscall::stat = 4

function name<T>(param: Type) -> Ret { ... }

Declares a function. Parameters are written name: Type and are never inferred; the return type follows -> and defaults to void. Declaration order does not matter: every signature is collected before any body is checked, so functions may call each other freely and recurse.

language reference

function sys_call0(num: Syscall) -> i64

(parameter) num: Syscall

type enum Syscall : i64 {
    read = 0;
    write = 1;
    open = 2;
    close = 3;
    stat = 4;
    fstat = 5;
    lstat = 6;
    poll = 7;
    lseek = 8;
    mmap = 9;
    // … 334 more
}

std::sys::syscall

function sys_call1(num: Syscall, a: i64) -> i64

(parameter) a: i64

function sys_call6(num: Syscall, a: i64, b: i64, c: i64, d: i64, e: i64, f: i64) -> i64

(parameter) b: i64

(parameter) c: i64

(parameter) d: i64

(parameter) e: i64

(parameter) f: i64

function sys_read(fd: i32, buf: u8*, count: u64) -> i64

(parameter) fd: i32

primitive i32

32-bit signed integer.

primitive type

(parameter) buf: u8*

primitive u8

8-bit unsigned integer.

primitive type

(parameter) count: u64

primitive u64

64-bit unsigned integer.

primitive type

function sys_write(fd: i32, buf: u8*, count: u64) -> i64

function sys_open(path: u8*, flags: i32, mode: u32) -> i32

(parameter) path: u8*

(parameter) flags: i32

(parameter) mode: u32

primitive u32

32-bit unsigned integer.

primitive type

function sys_close(fd: i32) -> i32

function sys_mmap(addr: u8*, length: u64, prot: i32, flags: i32, fd: i32, offset: i64) -> u8*

(parameter) addr: u8*

(parameter) length: u64

(parameter) prot: i32

(parameter) offset: i64

function sys_fork() -> i32

function sys_execve(path: u8*, argv: u8**, envp: u8**) -> i32

(parameter) argv: u8**

(parameter) envp: u8**

function sys_gettid() -> i32

function sys_pidfd_open(pid: i32, flags: u32) -> i32

(parameter) pid: i32

(parameter) flags: u32

function sys_clone3(args: u8*, size: u64) -> i64

(parameter) args: u8*

(parameter) size: u64

function sys_io_uring_setup(entries: u32, params: u8*) -> i32

(parameter) entries: u32

(parameter) params: u8*

type struct Name {
    field: Type;
    method(&this) -> Ret { ... }
}

A value type with named fields and optional methods. Structs live on the stack and are passed by value. Fields are public by default and may carry = default values; methods take their receiver as &this, mut &this, or this.

language reference

type struct FILETIME {
    dwLowDateTime: u32;
    dwHighDateTime: u32;
}

100-nanosecond intervals since 1601-01-01 UTC.

function name(count: i32, args...)

A variadic parameter: the trailing bucket receives any number of further arguments with C's calling convention, so the function stays ABI-compatible with the printf family. Wrap the bucket in VaArgs to read typed values from it.

language reference

type struct SYSTEMTIME {
    wYear: u16;
    wMonth: u16;
    wDayOfWeek: u16;
    wDay: u16;
    wHour: u16;
    wMinute: u16;
    wSecond: u16;
    wMilliseconds: u16;
}

type struct SECURITY_ATTRIBUTES {
    nLength: u32;
    lpSecurityDescriptor: u8*;
    bInheritHandle: i32;
}

Sized-and-attributed object passed to CreateFile, CreateMutex, etc.

type struct OVERLAPPED {
    Internal: u64;
    InternalHigh: u64;
    Offset: u32;
    OffsetHigh: u32;
    hEvent: u8*;
}

Overlapped I/O context (asynchronous file ops).

type struct STARTUPINFOA {
    cb: u32;
    lpReserved: u8*;
    lpDesktop: u8*;
    lpTitle: u8*;
    dwX: u32;
    dwY: u32;
    dwXSize: u32;
    dwYSize: u32;
    dwXCountChars: u32;
    dwYCountChars: u32;
    // … 8 more
}

CreateProcess startup parameters. lpReserved/lpDesktop/ lpTitle are typically null; size constants below.

type struct PROCESS_INFORMATION {
    hProcess: u8*;
    hThread: u8*;
    dwProcessId: u32;
    dwThreadId: u32;
}

type struct LARGE_INTEGER {
    QuadPart: i64;
}

LARGE_INTEGER for file sizes and QueryPerformanceCounter.

extern function exit(code: i32) -> void;
extern "C" {
    function puts(s: string) -> i32;
}

Declares a function whose body the linker supplies - typically a C library symbol. The compiler trusts the Cryo signature; keeping it in step with the real C signature is on you.

language reference

extern "C" function GetLastError() -> u32

extern "C" function CreateFileA(lpFileName: u8*, dwDesiredAccess: u32, dwShareMode: u32, lpSecurityAttributes: u8*, dwCreationDisposition: u32, dwFlagsAndAttributes: u32, hTemplateFile: u8*) -> u8*

primitive void

No value; only valid as a return type.

primitive type

extern "C" function VirtualAlloc(lpAddress: u8*, dwSize: u64, flAllocationType: u32, flProtect: u32) -> u8*

const NAME: Type = value;

At module level, a true compile-time constant, conventionally SCREAMING_SNAKE_CASE. (mut at module level declares mutable global state instead.)

language reference

const CLONE_VM: u64 = 0x00000100;

const CLONE_FS: u64 = 0x00000200;

const CLONE_FILES: u64 = 0x00000400;

const CLONE_SIGHAND: u64 = 0x00000800;

const CLONE_PIDFD: u64 = 0x00001000;

const CLONE_PTRACE: u64 = 0x00002000;

const CLONE_VFORK: u64 = 0x00004000;

const CLONE_PARENT: u64 = 0x00008000;

const CLONE_THREAD: u64 = 0x00010000;

const CLONE_NEWNS: u64 = 0x00020000;

const CLONE_SYSVSEM: u64 = 0x00040000;

const CLONE_SETTLS: u64 = 0x00080000;

const CLONE_PARENT_SETTID: u64 = 0x00100000;

const CLONE_CHILD_CLEARTID: u64 = 0x00200000;

const CLONE_DETACHED: u64 = 0x00400000;

const CLONE_UNTRACED: u64 = 0x00800000;

const CLONE_CHILD_SETTID: u64 = 0x01000000;

const CLONE_NEWCGROUP: u64 = 0x02000000;

const CLONE_NEWUTS: u64 = 0x04000000;

const CLONE_NEWIPC: u64 = 0x08000000;

const CLONE_NEWUSER: u64 = 0x10000000;

const CLONE_NEWPID: u64 = 0x20000000;

const CLONE_NEWNET: u64 = 0x40000000;

const CLONE_IO: u64 = 0x80000000;

const FUTEX_WAIT: i32 = 0;

const FUTEX_WAKE: i32 = 1;

const FUTEX_FD: i32 = 2;

const FUTEX_REQUEUE: i32 = 3;

const FUTEX_CMP_REQUEUE: i32 = 4;

const FUTEX_WAKE_OP: i32 = 5;

const FUTEX_LOCK_PI: i32 = 6;

const FUTEX_UNLOCK_PI: i32 = 7;

const FUTEX_TRYLOCK_PI: i32 = 8;

const FUTEX_WAIT_BITSET: i32 = 9;

const FUTEX_WAKE_BITSET: i32 = 10;

const FUTEX_WAIT_REQUEUE_PI: i32 = 11;

const FUTEX_CMP_REQUEUE_PI: i32 = 12;

const FUTEX_PRIVATE_FLAG: i32 = 128;

const FUTEX_CLOCK_REALTIME: i32 = 256;

const GRND_NONBLOCK: u32 = 1;

const GRND_RANDOM: u32 = 2;

const GRND_INSECURE: u32 = 4;

const PR_SET_PDEATHSIG: i32 = 1;

const PR_GET_PDEATHSIG: i32 = 2;

const PR_SET_DUMPABLE: i32 = 4;

const PR_GET_DUMPABLE: i32 = 3;

const PR_SET_NAME: i32 = 15;

const PR_GET_NAME: i32 = 16;

const PR_SET_SECCOMP: i32 = 22;

const PR_GET_SECCOMP: i32 = 21;

const PR_SET_NO_NEW_PRIVS: i32 = 38;

const PR_GET_NO_NEW_PRIVS: i32 = 39;

const SECCOMP_SET_MODE_STRICT: u32 = 0;

const SECCOMP_SET_MODE_FILTER: u32 = 1;

const SECCOMP_GET_ACTION_AVAIL: u32 = 2;

const SECCOMP_GET_NOTIF_SIZES: u32 = 3;

const PIDFD_NONBLOCK: u32 = 2048;

const INVALID_HANDLE_VALUE: i64 = -1;

const NULL_HANDLE: u64 = 0;

const STD_INPUT_HANDLE: u32 = 4294967286;

const STD_OUTPUT_HANDLE: u32 = 4294967285;

const STD_ERROR_HANDLE: u32 = 4294967284;

const STARTF_USESTDHANDLES: u32 = 0x100;

const HANDLE_FLAG_INHERIT: u32 = 0x1;

const DUPLICATE_SAME_ACCESS: u32 = 0x2;

const GENERIC_READ: u32 = 0x80000000;

const GENERIC_WRITE: u32 = 0x40000000;

const GENERIC_EXECUTE: u32 = 0x20000000;

const GENERIC_ALL: u32 = 0x10000000;

const FILE_SHARE_READ: u32 = 0x00000001;

const FILE_SHARE_WRITE: u32 = 0x00000002;

const FILE_SHARE_DELETE: u32 = 0x00000004;

const CREATE_NEW: u32 = 1;

const CREATE_ALWAYS: u32 = 2;

const OPEN_EXISTING: u32 = 3;

const OPEN_ALWAYS: u32 = 4;

const TRUNCATE_EXISTING: u32 = 5;

const FILE_ATTRIBUTE_READONLY: u32 = 0x1;

const FILE_ATTRIBUTE_HIDDEN: u32 = 0x2;

const FILE_ATTRIBUTE_SYSTEM: u32 = 0x4;

const FILE_ATTRIBUTE_DIRECTORY: u32 = 0x10;

const FILE_ATTRIBUTE_ARCHIVE: u32 = 0x20;

const FILE_ATTRIBUTE_NORMAL: u32 = 0x80;

const FILE_ATTRIBUTE_TEMPORARY: u32 = 0x100;

const FILE_ATTRIBUTE_REPARSE_POINT: u32 = 0x400;

const FILE_FLAG_WRITE_THROUGH: u32 = 0x80000000;

const FILE_FLAG_OVERLAPPED: u32 = 0x40000000;

const FILE_FLAG_NO_BUFFERING: u32 = 0x20000000;

const FILE_FLAG_RANDOM_ACCESS: u32 = 0x10000000;

const FILE_FLAG_SEQUENTIAL_SCAN: u32 = 0x08000000;

const FILE_FLAG_DELETE_ON_CLOSE: u32 = 0x04000000;

const FILE_FLAG_BACKUP_SEMANTICS: u32 = 0x02000000;

const FILE_FLAG_OPEN_REPARSE_POINT: u32 = 0x00200000;

const GetFileExInfoStandard: u32 = 0;

const FILE_BEGIN: u32 = 0;

const FILE_CURRENT: u32 = 1;

const FILE_END: u32 = 2;

const MEM_COMMIT: u32 = 0x1000;

const MEM_RESERVE: u32 = 0x2000;

const MEM_DECOMMIT: u32 = 0x4000;

const MEM_RELEASE: u32 = 0x8000;

const MEM_RESET: u32 = 0x80000;

const MEM_RESET_UNDO: u32 = 0x1000000;

const MEM_LARGE_PAGES: u32 = 0x20000000;

const MEM_PHYSICAL: u32 = 0x400000;

const MEM_TOP_DOWN: u32 = 0x100000;

const PAGE_NOACCESS: u32 = 0x01;

const PAGE_READONLY: u32 = 0x02;

const PAGE_READWRITE: u32 = 0x04;

const PAGE_WRITECOPY: u32 = 0x08;

const PAGE_EXECUTE: u32 = 0x10;

const PAGE_EXECUTE_READ: u32 = 0x20;

const PAGE_EXECUTE_READWRITE: u32 = 0x40;

const PAGE_EXECUTE_WRITECOPY: u32 = 0x80;

const PAGE_GUARD: u32 = 0x100;

const PAGE_NOCACHE: u32 = 0x200;

const WAIT_OBJECT_0: u32 = 0;

const WAIT_ABANDONED_0: u32 = 0x80;

const WAIT_TIMEOUT: u32 = 0x102;

const WAIT_FAILED: u32 = 0xFFFFFFFF;

const INFINITE: u32 = 0xFFFFFFFF;

const HEAP_NO_SERIALIZE: u32 = 0x1;

const HEAP_GROWABLE: u32 = 0x2;

const HEAP_GENERATE_EXCEPTIONS: u32 = 0x4;

const HEAP_ZERO_MEMORY: u32 = 0x8;

const HEAP_REALLOC_IN_PLACE_ONLY: u32 = 0x10;

const CREATE_SUSPENDED: u32 = 0x4;

const DETACHED_PROCESS: u32 = 0x8;

const CREATE_NEW_CONSOLE: u32 = 0x10;

const CREATE_NEW_PROCESS_GROUP: u32 = 0x200;

const CREATE_UNICODE_ENVIRONMENT: u32 = 0x400;

const CREATE_BREAKAWAY_FROM_JOB: u32 = 0x1000000;

const CREATE_NO_WINDOW: u32 = 0x8000000;

const ERROR_SUCCESS: u32 = 0;

const ERROR_FILE_NOT_FOUND: u32 = 2;

const ERROR_PATH_NOT_FOUND: u32 = 3;

const ERROR_ACCESS_DENIED: u32 = 5;

const ERROR_INVALID_HANDLE: u32 = 6;

const ERROR_NOT_ENOUGH_MEMORY: u32 = 8;

const ERROR_BAD_FORMAT: u32 = 11;

const ERROR_INVALID_DATA: u32 = 13;

const ERROR_NO_MORE_FILES: u32 = 18;

const ERROR_SHARING_VIOLATION: u32 = 32;

const ERROR_HANDLE_EOF: u32 = 38;

const ERROR_NOT_SUPPORTED: u32 = 50;

const ERROR_FILE_EXISTS: u32 = 80;

const ERROR_INVALID_PARAMETER: u32 = 87;

const ERROR_BROKEN_PIPE: u32 = 109;

const ERROR_DISK_FULL: u32 = 112;

const ERROR_INSUFFICIENT_BUFFER: u32 = 122;

const ERROR_INVALID_NAME: u32 = 123;

const ERROR_ALREADY_EXISTS: u32 = 183;

const ERROR_NO_DATA: u32 = 232;

const ERROR_PIPE_BUSY: u32 = 231;

const ERROR_MORE_DATA: u32 = 234;

const ERROR_NO_MORE_ITEMS: u32 = 259;

const ERROR_DIRECTORY: u32 = 267;

const ERROR_OPERATION_ABORTED: u32 = 995;

const ERROR_IO_INCOMPLETE: u32 = 996;

const ERROR_IO_PENDING: u32 = 997;

const ERROR_TIMEOUT: u32 = 1460;

const STATUS_SUCCESS: u32 = 0;

const STATUS_PENDING: u32 = 259;

const STATUS_BUFFER_OVERFLOW: u32 = 0x80000005;

const STATUS_NO_MORE_FILES: u32 = 0x80000006;

const STATUS_INVALID_HANDLE: u32 = 0xC0000008;

const STATUS_INVALID_PARAMETER: u32 = 0xC000000D;

const STATUS_END_OF_FILE: u32 = 0xC0000011;

const STATUS_ACCESS_DENIED: u32 = 0xC0000022;

const FORMAT_MESSAGE_ALLOCATE_BUFFER: u32 = 0x100;

const FORMAT_MESSAGE_IGNORE_INSERTS: u32 = 0x200;

const FORMAT_MESSAGE_FROM_STRING: u32 = 0x400;

const FORMAT_MESSAGE_FROM_HMODULE: u32 = 0x800;

const FORMAT_MESSAGE_FROM_SYSTEM: u32 = 0x1000;

const FORMAT_MESSAGE_ARGUMENT_ARRAY: u32 = 0x2000;

const ENABLE_PROCESSED_INPUT: u32 = 0x1;

const ENABLE_LINE_INPUT: u32 = 0x2;

const ENABLE_ECHO_INPUT: u32 = 0x4;

const ENABLE_WINDOW_INPUT: u32 = 0x8;

const ENABLE_MOUSE_INPUT: u32 = 0x10;

const ENABLE_INSERT_MODE: u32 = 0x20;

const ENABLE_QUICK_EDIT_MODE: u32 = 0x40;

const ENABLE_EXTENDED_FLAGS: u32 = 0x80;

const ENABLE_PROCESSED_OUTPUT: u32 = 0x1;

const ENABLE_WRAP_AT_EOL_OUTPUT: u32 = 0x2;

const ENABLE_VIRTUAL_TERMINAL_PROCESSING: u32 = 0x4;

const ENABLE_VIRTUAL_TERMINAL_INPUT: u32 = 0x200;

const CP_ACP: u32 = 0;

const CP_OEMCP: u32 = 1;

const CP_UTF7: u32 = 65000;

const CP_UTF8: u32 = 65001;

const MB_OK: u32 = 0;

const MB_OKCANCEL: u32 = 1;

const MB_ABORTRETRYIGNORE: u32 = 2;

const MB_YESNOCANCEL: u32 = 3;

const MB_YESNO: u32 = 4;

const MB_RETRYCANCEL: u32 = 5;

const MB_ICONERROR: u32 = 0x10;

const MB_ICONWARNING: u32 = 0x30;

const MB_ICONINFORMATION: u32 = 0x40;

const IDOK: i32 = 1;

const IDCANCEL: i32 = 2;

const IDABORT: i32 = 3;

const IDRETRY: i32 = 4;

const IDIGNORE: i32 = 5;

const IDYES: i32 = 6;

const IDNO: i32 = 7;

const HKEY_CLASSES_ROOT: u64 = 0xFFFFFFFF80000000;

const HKEY_CURRENT_USER: u64 = 0xFFFFFFFF80000001;

const HKEY_LOCAL_MACHINE: u64 = 0xFFFFFFFF80000002;

const HKEY_USERS: u64 = 0xFFFFFFFF80000003;

const HKEY_CURRENT_CONFIG: u64 = 0xFFFFFFFF80000005;

const KEY_QUERY_VALUE: u32 = 0x1;

const KEY_SET_VALUE: u32 = 0x2;

const KEY_CREATE_SUB_KEY: u32 = 0x4;

const KEY_ENUMERATE_SUB_KEYS: u32 = 0x8;

const KEY_NOTIFY: u32 = 0x10;

const KEY_READ: u32 = 0x20019;

const KEY_WRITE: u32 = 0x20006;

const KEY_ALL_ACCESS: u32 = 0xF003F;

const REG_NONE: u32 = 0;

const REG_SZ: u32 = 1;

const REG_EXPAND_SZ: u32 = 2;

const REG_BINARY: u32 = 3;

const REG_DWORD: u32 = 4;

const REG_DWORD_BIG_ENDIAN: u32 = 5;

const REG_MULTI_SZ: u32 = 7;

const REG_QWORD: u32 = 11;

const INVALID_SOCKET: u64 = 18446744073709551615;

const SOCKET_ERROR: i32 = -1;

const WSAEINTR: i32 = 10004;

const WSAEWOULDBLOCK: i32 = 10035;

const WSAEADDRINUSE: i32 = 10048;

const WSAECONNRESET: i32 = 10054;

const WSAECONNREFUSED: i32 = 10061;

const WSAETIMEDOUT: i32 = 10060;

const WSAECONNABORTED: i32 = 10053;

const WSAENOTCONN: i32 = 10057;

const FIONBIO: i32 = -2147195266;

const SOL_SOCKET: i32 = 65535;

const SO_ERROR: i32 = 4103;

const SO_CONNECT_TIME: i32 = 28684;

const SO_CONNECT_TIME_NEVER: u32 = 0xFFFFFFFF;

const IOCTL_AFD_POLL: u32 = 0x00012024;

const AFD_POLL_RECEIVE: u32 = 0x0001;

const AFD_POLL_RECEIVE_EXPEDITED: u32 = 0x0002;

const AFD_POLL_SEND: u32 = 0x0004;

const AFD_POLL_DISCONNECT: u32 = 0x0008;

const AFD_POLL_ABORT: u32 = 0x0010;

const AFD_POLL_LOCAL_CLOSE: u32 = 0x0020;

const AFD_POLL_ACCEPT: u32 = 0x0080;

const AFD_POLL_CONNECT_FAIL: u32 = 0x0100;

const SIZEOF_IO_STATUS_BLOCK: u64 = 16;

const SIZEOF_OVERLAPPED: u64 = 32;

const SIZEOF_AFD_POLL_INFO: u64 = 32;

const SIZEOF_OBJECT_ATTRIBUTES: u64 = 48;

const SIZEOF_UNICODE_STRING: u64 = 16;

const SIZEOF_OVERLAPPED_ENTRY: u64 = 32;

const SYNCHRONIZE: u32 = 0x00100000;

const FILE_SHARE_RW: u32 = 3;

const FILE_OPEN: u32 = 1;

const SIO_BASE_HANDLE: u32 = 0x48000022;

const IOCP_KICK_KEY: u64 = 1;

import a::b;
import a::b::{ X, Y };
import a::b as c;
import a::b::*;

Brings a module, or selected items from it, into scope. One path per declaration: use the brace form for several items, as to alias, and * for everything public (prefer the brace form; wildcards invite name collisions).

language reference

namespace std;

std: the Cryo standard library.

module page

namespace std::sys;

sys: the low-level OS seam.

module page

namespace std::sys::syscall;

syscall: raw system-call bindings, gated per platform.

module page

function sys_read(fd: i32, buf: u8*, count: u64) -> i64

std::sys::syscall

function sys_clone3(args: u8*, size: u64) -> i64

std::sys::syscall

function sys_io_uring_setup(entries: u32, params: u8*) -> i32

std::sys::syscall

function sys_call0(num: Syscall) -> i64

std::sys::syscall

function sys_call6(num: Syscall, a: i64, b: i64, c: i64, d: i64, e: i64, f: i64) -> i64

std::sys::syscall

extern "C" function syscall(number: Syscall, ...) -> i64

std::sys::syscall

type struct FILETIME {
    dwLowDateTime: u32;
    dwHighDateTime: u32;
}

100-nanosecond intervals since 1601-01-01 UTC.

std::sys::syscall

type struct STARTUPINFOA {
    cb: u32;
    lpReserved: u8*;
    lpDesktop: u8*;
    lpTitle: u8*;
    dwX: u32;
    dwY: u32;
    dwXSize: u32;
    dwYSize: u32;
    dwXCountChars: u32;
    dwYCountChars: u32;
    // … 8 more
}

CreateProcess startup parameters. lpReserved/lpDesktop/ lpTitle are typically null; size constants below.

std::sys::syscall

type struct PROCESS_INFORMATION {
    hProcess: u8*;
    hThread: u8*;
    dwProcessId: u32;
    dwThreadId: u32;
}

std::sys::syscall

Syscall::gettid = 186

std::sys::syscall

Syscall::pidfd_open = 434

std::sys::syscall

Syscall::io_uring_setup = 425

std::sys::syscall

Syscall::bpf = 321

std::sys::syscall

Syscall::userfaultfd = 323

std::sys::syscall

Syscall::clone3 = 435

std::sys::syscall

Two surfaces, gated by target#

When to reach for this instead of ffi::libc#

ABI notes#

Constants#

Two surfaces, gated by target

When to reach for this instead of `ffi::libc`

ABI notes

Constants