Module errno

Overview

The errno module is typically used within a function or within a Lua program, in association with a module whose functions can return operating-system errors, such as fio.

Index

Below is a list of all errno functions.

errno()

Return an error number for the last operating-system-related function, or 0. To invoke it, simply say errno(), without the module name.

Rtype:	integer

errno.strerror([code])¶

Return a string, given an error number. The string will contain the text of the conventional error message for the current operating system. If code is not supplied, the error message will be for the last operating-system-related function, or 0.

Parameters:	code (integer) – number of an operating-system error
Rtype:	string

Example:

This function displays the result of a call to fio.open() which causes error 2 (errno.ENOENT). The display includes the error number, the associated error string, and the error name.

tarantool> function f()
         >   local fio = require('fio')
         >   local errno = require('errno')
         >   fio.open('no_such_file')
         >   print('errno() = ' .. errno())
         >   print('errno.strerror() = ' .. errno.strerror())
         >   local t = getmetatable(errno).__index
         >   for k, v in pairs(t) do
         >     if v == errno() then
         >       print('errno() constant = ' .. k)
         >     end
         >   end
         > end
---
...

tarantool> f()
errno() = 2
errno.strerror() = No such file or directory
errno() constant = ENOENT
---
...

To see all possible error names stored in the errno metatable, say getmetatable(errno) (output abridged):

tarantool> getmetatable(errno)
---
- __newindex: 'function: 0x41666a38'
  __call: 'function: 0x41666890'
  __index:
  ENOLINK: 67
  EMSGSIZE: 90
  EOVERFLOW: 75
  ENOTCONN: 107
  EFAULT: 14
  EOPNOTSUPP: 95
  EEXIST: 17
  ENOSR: 63
  ENOTSOCK: 88
  EDESTADDRREQ: 89
  <...>
...