Module

std::libc::errno

LibC Errno

Thread-local errno access and POSIX error constants, exposed as LibC::Errno.

Functions

Function	Description
`get`	Read the current thread-local `errno` value
`set`	Write a new value into thread-local `errno`

Error Constants

All error constants are extern const declarations resolved from <errno.h> at compile time.

Constant	Description
`EPERM`	Operation not permitted
`ENOENT`	No such file or directory
`ESRCH`	No such process
`EINTR`	Interrupted system call
`EIO`	I/O error
`ENXIO`	No such device or address
`E2BIG`	Argument list too long
`EACCES`	Permission denied
`EBADF`	Bad file descriptor
`EAGAIN`	Resource temporarily unavailable
`ENOMEM`	Cannot allocate memory
`EBUSY`	Resource busy
`EEXIST`	File exists
`ENOTDIR`	Not a directory
`EISDIR`	Is a directory
`EINVAL`	Invalid argument
`ENFILE`	Too many open files in system
`EMFILE`	Too many open files (per process)
`ENOSPC`	No space left on device
`EROFS`	Read-only file system
`EPIPE`	Broken pipe
`ERANGE`	Result too large (math)
`ENOTEMPTY`	Directory not empty
`ECONNREFUSED`	Connection refused
`ECONNRESET`	Connection reset by peer
`ETIMEDOUT`	Connection timed out
`EWOULDBLOCK`	Alias for `EAGAIN`

Platform Notes

On Linux/glibc, errno is a macro expanding to (*__errno_location()). The get and set functions call __errno_location to read/write the thread-local value.

Example

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

function main(): i32 {
  let fd: CType::CInt = LibC::File::open("/nonexistent", LibC::File::O_RDONLY);
  if fd == -1 {
    let err: CType::CInt = LibC::Errno::get();
    if err == LibC::Errno::ENOENT {
      // file not found -- expected
      return 0;
    }
  }
  return 1;
}

namespace __errno

Functions

function errno_location(): *mut i32

Returns the thread-local errno pointer on Linux.

namespace __errno_constants

Returns the thread-local errno pointer on macOS.

Constants

const E2BIG: i32

const EACCES: i32

const EAGAIN: i32

const EBADF: i32

const EBUSY: i32

const ECONNREFUSED: i32

const ECONNRESET: i32

const EEXIST: i32

const EINTR: i32

const EINVAL: i32

const EIO: i32

const EISDIR: i32

const EMFILE: i32

const ENFILE: i32

const ENOENT: i32

const ENOMEM: i32

const ENOSPC: i32

const ENOTDIR: i32

const ENOTEMPTY: i32

const ENXIO: i32

const EPERM: i32

const EPIPE: i32

const ERANGE: i32

const EROFS: i32

const ESRCH: i32

const ETIMEDOUT: i32

namespace Errno

Thread-local error number and POSIX error constants.

Functions

function get(): i32

Reads the current errno value.

function set(value: i32): void

Sets errno to value.

Constants

const E2BIG: i32

const EACCES: i32

const EAGAIN: i32

const EBADF: i32

const EBUSY: i32

const ECONNREFUSED: i32

const ECONNRESET: i32

const EEXIST: i32

const EINTR: i32

const EINVAL: i32

const EIO: i32

const EISDIR: i32

const EMFILE: i32

const ENFILE: i32

const ENOENT: i32

const ENOMEM: i32

const ENOSPC: i32

const ENOTDIR: i32

const ENOTEMPTY: i32

const ENXIO: i32

const EPERM: i32

const EPIPE: i32

const ERANGE: i32

const EROFS: i32

const ESRCH: i32

const ETIMEDOUT: i32

const EWOULDBLOCK: i32