Vasudev Ram: Show error numbers and codes from the os.errno module

By Vasudev Ram

While browsing the Python standard library docs, in particular the module os.errno, I got the idea of writing this small utility to display os.errno error codes and error names, which are stored in the dict os.errno.errorcode:

Here is the program, os_errno_info.py:

from __future__ import print_function
'''
os_errno_info.py
To show the error codes and 
names from the os.errno module.
Author: Vasudev Ram
Copyright 2017 Vasudev Ram
Web site: https://vasudevram.github.io
Blog: https://jugad2.blogspot.com
Product store: https://gumroad.com/vasudevram
'''

import sys
import os

def main():

    print("Showing error codes and names\nfrom the os.errno module:")
    print("Python sys.version:", sys.version[:6])
    print("Number of error codes:", len(os.errno.errorcode))
    print("{0:>4}{1:>8}   {2:<20}    {3:<}".format(\
"Idx", "Code", "Name", "Message"))
    for idx, key in enumerate(sorted(os.errno.errorcode)):
        print("{0:>4}{1:>8}   {2:<20}    {3:<}".format(\
            idx, key, os.errno.errorcode[key], os.strerror(key)))

if __name__ == '__main__':
    main()

And here is the output on running it:

$ py -2 os_errno_info.py >out2 && gvim out2
Showing error codes and names
from the os.errno module:
Python sys.version: 2.7.12
Number of error codes: 86
 Idx    Code   Name                    Message
   0       1   EPERM                   Operation not permitted
   1       2   ENOENT                  No such file or directory
   2       3   ESRCH                   No such process
   3       4   EINTR                   Interrupted function call
   4       5   EIO                     Input/output error
   5       6   ENXIO                   No such device or address
   6       7   E2BIG                   Arg list too long
   7       8   ENOEXEC                 Exec format error
   8       9   EBADF                   Bad file descriptor
   9      10   ECHILD                  No child processes
  10      11   EAGAIN                  Resource temporarily unavailable
  11      12   ENOMEM                  Not enough space
  12      13   EACCES                  Permission denied
  13      14   EFAULT                  Bad address
  14      16   EBUSY                   Resource device
  15      17   EEXIST                  File exists
  16      18   EXDEV                   Improper link
  17      19   ENODEV                  No such device
  18      20   ENOTDIR                 Not a directory
  19      21   EISDIR                  Is a directory
  20      22   EINVAL                  Invalid argument
  21      23   ENFILE                  Too many open files in system
  22      24   EMFILE                  Too many open files
  23      25   ENOTTY                  Inappropriate I/O control operation
  24      27   EFBIG                   File too large
  25      28   ENOSPC                  No space left on device
  26      29   ESPIPE                  Invalid seek
  27      30   EROFS                   Read-only file system
  28      31   EMLINK                  Too many links
  29      32   EPIPE                   Broken pipe
  30      33   EDOM                    Domain error
  31      34   ERANGE                  Result too large
  32      36   EDEADLOCK               Resource deadlock avoided
  33      38   ENAMETOOLONG            Filename too long
  34      39   ENOLCK                  No locks available
  35      40   ENOSYS                  Function not implemented
  36      41   ENOTEMPTY               Directory not empty
  37      42   EILSEQ                  Illegal byte sequence
  38   10000   WSABASEERR              Unknown error
  39   10004   WSAEINTR                Unknown error
  40   10009   WSAEBADF                Unknown error
  41   10013   WSAEACCES               Unknown error
  42   10014   WSAEFAULT               Unknown error
  43   10022   WSAEINVAL               Unknown error
  44   10024   WSAEMFILE               Unknown error
  45   10035   WSAEWOULDBLOCK          Unknown error
  46   10036   WSAEINPROGRESS          Unknown error
  47   10037   WSAEALREADY             Unknown error
  48   10038   WSAENOTSOCK             Unknown error
  49   10039   WSAEDESTADDRREQ         Unknown error
  50   10040   WSAEMSGSIZE             Unknown error
  51   10041   WSAEPROTOTYPE           Unknown error
  52   10042   WSAENOPROTOOPT          Unknown error
  53   10043   WSAEPROTONOSUPPORT      Unknown error
  54   10044   WSAESOCKTNOSUPPORT      Unknown error
  55   10045   WSAEOPNOTSUPP           Unknown error
  56   10046   WSAEPFNOSUPPORT         Unknown error
  57   10047   WSAEAFNOSUPPORT         Unknown error
  58   10048   WSAEADDRINUSE           Unknown error
  59   10049   WSAEADDRNOTAVAIL        Unknown error
  60   10050   WSAENETDOWN             Unknown error
  61   10051   WSAENETUNREACH          Unknown error
  62   10052   WSAENETRESET            Unknown error
  63   10053   WSAECONNABORTED         Unknown error
  64   10054   WSAECONNRESET           Unknown error
  65   10055   WSAENOBUFS              Unknown error
  66   10056   WSAEISCONN              Unknown error
  67   10057   WSAENOTCONN             Unknown error
  68   10058   WSAESHUTDOWN            Unknown error
  69   10059   WSAETOOMANYREFS         Unknown error
  70   10060   WSAETIMEDOUT            Unknown error
  71   10061   WSAECONNREFUSED         Unknown error
  72   10062   WSAELOOP                Unknown error
  73   10063   WSAENAMETOOLONG         Unknown error
  74   10064   WSAEHOSTDOWN            Unknown error
  75   10065   WSAEHOSTUNREACH         Unknown error
  76   10066   WSAENOTEMPTY            Unknown error
  77   10067   WSAEPROCLIM             Unknown error
  78   10068   WSAEUSERS               Unknown error
  79   10069   WSAEDQUOT               Unknown error
  80   10070   WSAESTALE               Unknown error
  81   10071   WSAEREMOTE              Unknown error
  82   10091   WSASYSNOTREADY          Unknown error
  83   10092   WSAVERNOTSUPPORTED      Unknown error
  84   10093   WSANOTINITIALISED       Unknown error
  85   10101   WSAEDISCON              Unknown error

In the above Python command line, you can of course skip the "&& gvim out2" part. It is just there to automatically open the output file in gVim (text editor) after the utility runs.

The above output was from running it with Python 2.
The utility is written to also work with Python 3.
To change the command line to use Python 3, just change 2 to 3 everywhere in the above Python command :)
(You need to install or already have py, the Python Launcher for Windows, for the py command to work. If you don't have it, or are not on Windows, use python instead of py -2 or py -3 in the above python command line - after having set your OS PATH to point to Python 2 or Python 3 as wanted.)

The only differences in the output are the version message (2.x vs 3.x), and the number of error codes - 86 in Python 2 vs. 101 in Python 3.
Unix people will recognize many of the messages (EACCES, ENOENT, EBADF, etc.) as being familiar ones that you get while programming on Unix.
The error names starting with W are probably Windows-specific errors. Not sure how to get the messages for those, need to look it up. (It currently shows "Unknown error" for them.)

This above Python utility was inspired by an earlier auxiliary utility I wrote, called showsyserr.c, as part of my IBM developerWorks article, Developing a Linux command-line utility (not the main utility described in the article). Following (recursively) the link in the previous sentence will lead you to the code for both the auxiliary and the main utility, as well as the PDF version of the article.

Enjoy.

- Vasudev Ram - Online Python training and consulting

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