Question

For some code as follows,

    opts, args = getopt.getopt(sys.argv[1:], “c:”, …

    for o,v in opts:

…

        elif o in (“-c”, “–%s” % checkString):

            kCheckOnly = True

            clientTemp = v

If I don’t give the parameter after the -c, I get the error messages as follows.

Traceback (most recent call last):

  File “niFpgaTimingViolationMain.py”, line 100, in

    opts, args = getopt.getopt(sys.argv[1:], “hdc:t:”,[helpString, debugString, checkString, twxString])

  File “/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/getopt.py”, line 91, in getopt

    opts, args = do_shorts(opts, args[0][1:], shortopts, args[1:])

  File “/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/getopt.py”, line 195, in do_shorts

    opt)

getopt.GetoptError: option -c requires argument

Is there any way to catch this error, and process it to print something like this? It seems that just wrapping the code in try/except doesn’t work.

ERROR: You forgot to give the file name after -c option

Answer 1

You can catch getopt.GetoptError and check the ‘opt’ and ‘msg’ attributes yourself:

try:
    opts, args = getopt.getopt(sys.argv[1:], "c:", ...
except getopt.GetoptError, e:
    if e.opt == 'c' and 'requires argument' in e.msg:
        print >>sys.stderr, 'ERROR: You forgot to give the file name after -c option'
        sys.exit(-1)