errnolookup.py

#!/usr/bin/env python
 
import sys
import errno
import ctypes
 
try:
	libc = ctypes.CDLL('libc.dylib')
except OSError:
	libc = ctypes.CDLL('/lib/libc.so.6')
 
errorcode = int(sys.argv[1])
errmsg = ctypes.c_char_p(libc.strerror(errorcode)).value
 
print "%s (%d): %s" % (errno.errorcode[errorcode], errorcode, errmsg,)

example.txt

> ./errnolookup.py 1
EPERM (1): Operation not permitted
> ./errnolookup.py 2
ENOENT (2): No such file or directory
> ./errnolookup.py 3
ESRCH (3): No such process
> ./errnolookup.py 42
ENOMSG (42): No message of desired type