// libc bindings:
//   https://www.man7.org/linux/man-pages/man2/<libc call>.2.html

// The buffers are i64 addresses of zero-terminated strings.
//     i64 buf = aryu8.str0("some_file");
// buf mode perm-> fd
{  i64 i32  i32 -> i32 } open = "C";
// buf perm -> fd
{  i64 i32 -> i32 } creat = "C";

// fd  buf len -> len
{  i32 i64 i64 -> i64 } write = "C";
// fd  buf len -> len
{  i32 i64 i64 -> i64 } read = "C";
// fd  -> err
{  i32 -> i32 } close = "C";
// path -> err
{  i64 -> i32 } unlink = "C";

i32 O_RDONLY = 0;
i32 O_WRONLY = 1;
i32 O_RDWR   = 2;
i32 O_CREAT = 512; // 02000 on x86_64-pc-cygwin
i32 O_TRUNC = 1024; // 04000 on x86_64-pc-cygwin

i32 STDIN  = 0;
i32 STDOUT = 1;
i32 STDERR = 2;
i32 EOF    = -1; // simple_getch sets errno to EOF on end-of-input.

// status
{  i32 -> i32 } _exit = "C";

// errno is not an ordinary C data symbol; read it through the native runtime.
{ i32 } simple_errno = "C";
val errno = { -> simple_errno(); };
{ i32 -> i32 } simple_set_errno = "C";
// Set errno and return -1, matching the native I/O error convention.
val set_errno = { i32 error -> simple_set_errno(error); };

i32 EINTR = "C";
i32 EIO = "C";
i32 EINVAL = "C";
i32 EOVERFLOW = "C";

// Read one byte from stdin, without <enter> or echo.  Restores the previous
// terminal mode before returning.  Files and pipes also work.  Returns 0..255,
// or -1 with errno set to EOF or an OS error.  Ctrl-C is byte 3; escape/UTF-8
// sequences are multiple bytes.
{ i32 } simple_getch = "C";

// addr len prot flags fd  off -> void*
{  i64  i64 i32  i32   i32 i32 -> i64 } mmap = "C";
// mmap flags
i32 PROT_EXEC = 4;
i32 PROT_READ = 1;
i32 PROT_WRITE= 2;
i32 PROT_NONE = 0;
i32 MAP_PRIVATE = 2;
i32 MAP_ANON = 32;