Re: [PATCH 4/4] app/testpmd: enhance getopt_long usage

[Ferruh Yigit <ferruh.yigit@amd.com>]

On 3/13/2024 4:51 PM, David Marchand wrote:

<...>

>>
>> And just after while loop, there is "if (optind != argc)" check, I don't
>> see when this check will be hit, so it looks useless.
> But this part actually looks correct to me.
> We could still hit this part with non handled trailing strings:
> 
> $ build-mini/app/dpdk-testpmd -c 3 --no-huge -m 40 -a 0:0.0 --vdev
> net_null1 --vdev net_null2 -- -i garbage
> Invalid parameter: garbage
> EAL: Error - exiting with code: 1
>   Cause: Command line is incorrect
> Port 0 is closed
> Port 1 is closed
>

OK, I see it is to catch non-option argument and works as expected.

I missed that when 'getopt_long()' returns -1 (EOF), it sets 'optind' to
point first non-option argument in argv, and does this by swapping
elements in argv[] (I wasn't aware 'getopt_long()' does this).


Since testpmd doesn't get any non-option argument, it can be possible to
prefix 'short_options' with '+', (like "+ah"), which modify
'getopt_long()' behavior to stop when first non-option argument seen.

This prevents some unnecessary argument parsing, but it seems this is a
GNU extension, not posix standard, so not sure does it worth this
optimization.