Module

std::libc::io

LibC I/O

POSIX file-descriptor operations from unistd.h and fcntl.h, exposed as LibC::File.

Constants

Constant	Description
`SEEK_SET`	Seek from beginning of file
`SEEK_CUR`	Seek from current position
`SEEK_END`	Seek from end of file
`STDIN_FILENO`	Standard input fd (0)
`STDOUT_FILENO`	Standard output fd (1)
`STDERR_FILENO`	Standard error fd (2)
`O_RDONLY`	Open for reading only
`O_WRONLY`	Open for writing only
`O_RDWR`	Open for reading and writing
`O_CREAT`	Create file if it does not exist
`O_TRUNC`	Truncate file to zero length
`O_APPEND`	Append on each write
`F_GETFD`	`fcntl` request: get fd flags
`F_SETFD`	`fcntl` request: set fd flags
`FD_CLOEXEC`	Close fd on successful `exec`

Functions

Function	Description
`open`	Open file by pathname
`close`	Close file descriptor
`read`	Read bytes from file descriptor
`write`	Write bytes to file descriptor
`lseek`	Reposition file offset
`unlink`	Delete filesystem name
`rmdir`	Remove empty directory
`getcwd`	Get current working directory
`chdir`	Change working directory
`dup`	Duplicate file descriptor
`dup2`	Duplicate fd to specific number
`isatty`	Test if fd refers to a terminal
`fcntl`	Run `fcntl(fd, cmd)`
`fcntlArg`	Run `fcntl(fd, cmd, arg)`

Most functions return -1 on error. read returns 0 on EOF.

Example

import LibC, CType from "std::libc";

function main(): i32 {
  let fd: CType::CInt = LibC::File::open(
    "hello.txt",
    LibC::File::O_WRONLY | LibC::File::O_CREAT | LibC::File::O_TRUNC,
  );
  if fd == -1 {
    return 1;
  }
  let data: *u8 = "hello, world\n";
  LibC::File::write(fd, data as CType::CConstVoidPtr, 13);
  LibC::File::close(fd);
  return 0;
}

namespace __fcntl

Functions

function fcntl(fd: i32, cmd: i32): i32

POSIX fcntl(fd, cmd) for commands without a third argument.

function fcntlArg(fd: i32, cmd: i32, arg: i32): i32

POSIX fcntl(fd, cmd, arg) for integer descriptor-flag commands.

Constants

const F_GETFD: i32

const F_SETFD: i32

const FD_CLOEXEC: i32

const O_APPEND: i32

const O_CREAT: i32

const O_RDONLY: i32

const O_RDWR: i32

const O_TRUNC: i32

const O_WRONLY: i32

namespace __unistd_io

Functions

function chdir(path: *u8): i32

POSIX chdir; changes the current working directory.

function close(fd: i32): i32

POSIX close; returns 0 on success or -1.

function dup(oldfd: i32): i32

POSIX dup; duplicates a file descriptor.

function dup2(oldfd: i32, newfd: i32): i32

POSIX dup2; duplicates a descriptor to a requested number.

function getcwd(buf: *mut u8, size: u64): *mut u8

POSIX getcwd; writes the current directory into buf.

function isatty(fd: i32): i32

POSIX isatty; returns nonzero when fd is a terminal.

function lseek(fd: i32, offset: i64, whence: i32): i64

POSIX lseek; returns the resulting offset or -1.

function open(pathname: *u8, flags: i32): i32

POSIX open with flags; returns a file descriptor or -1.

function read(fd: i32, buf: *mut void, count: u64): i64

POSIX read; returns bytes read, 0 on EOF, or -1 on error.

function rmdir(pathname: *u8): i32

POSIX rmdir; removes an empty directory.

function unlink(pathname: *u8): i32

POSIX unlink; removes a filesystem name.

function write(fd: i32, buf: *void, count: u64): i64

POSIX write; returns bytes written or -1 on error.

Constants

const SEEK_CUR: i32

const SEEK_END: i32

const SEEK_SET: i32

const STDERR_FILENO: i32

const STDIN_FILENO: i32

const STDOUT_FILENO: i32

namespace File

POSIX file descriptors (unistd.h / fcntl.h)

Functions

function chdir(path: *u8): i32

Changes the current working directory to path.

function close(fd: i32): i32

Closes file descriptor fd. Returns 0 on success, -1 on error.

function dup(oldfd: i32): i32

Duplicates file descriptor oldfd. Returns the new fd or -1.

function dup2(oldfd: i32, newfd: i32): i32

Duplicates oldfd to newfd, closing newfd first if open.

function fcntl(fd: i32, cmd: i32): i32

Performs fcntl(fd, cmd) for commands without a third argument.

function fcntlArg(fd: i32, cmd: i32, arg: i32): i32

Performs fcntl(fd, cmd, arg) for commands that require an integer value.

function getcwd(buf: *mut u8, size: u64): *mut u8

Writes the current working directory into buf (up to size bytes).

function isatty(fd: i32): i32

Tests whether fd refers to a terminal. Returns 1 if true.

function lseek(fd: i32, offset: i64, whence: i32): i64

Repositions the file offset of fd. Use SEEK_SET/CUR/END for whence.

Returns the new offset, or -1 on error.

function open(pathname: *u8, flags: i32): i32

Opens the file at pathname with the given flags.

Returns a file descriptor, or -1 on error.

function read(fd: i32, buf: *mut void, count: u64): i64

Reads up to count bytes from file descriptor fd into buf.

Returns the number of bytes read, 0 on EOF, or -1 on error.

function rmdir(pathname: *u8): i32

Removes an empty directory. Returns 0 on success.

function unlink(pathname: *u8): i32

Deletes a name from the filesystem. Returns 0 on success.

function write(fd: i32, buf: *void, count: u64): i64

Writes up to count bytes from buf to file descriptor fd.

Returns the number of bytes written, or -1 on error.

Constants

const F_GETFD: i32

const F_SETFD: i32

const FD_CLOEXEC: i32

const O_APPEND: i32

const O_CREAT: i32

const O_RDONLY: i32

const O_RDWR: i32

const O_TRUNC: i32

const O_WRONLY: i32

const SEEK_CUR: i32

const SEEK_END: i32

const SEEK_SET: i32

const STDERR_FILENO: i32

const STDIN_FILENO: i32

const STDOUT_FILENO: i32