[dpdk-dev] [PATCH v3 07/11] eal: add log level help

[Stephen Hemminger]

On Mon, 15 Mar 2021 11:52:13 +0100
Thomas Monjalon <thomas at monjalon.net> wrote:

> 15/03/2021 11:42, Kinsella, Ray:
> > 
> > On 15/03/2021 10:31, Bruce Richardson wrote:  
> > > On Mon, Mar 15, 2021 at 10:19:47AM +0000, Kinsella, Ray wrote:  
> > >>
> > >>
> > >> On 12/03/2021 18:17, Thomas Monjalon wrote:  
> > >>> The option --log-level was not completely described in the usage text,
> > >>> and it was difficult to guess the names of the log types and levels.
> > >>>
> > >>> A new value "help" is accepted after --log-level to give more details
> > >>> about the syntax and listing the log types and levels.
> > >>>
> > >>> The array "levels" used for level name parsing is replaced with
> > >>> a (modified) existing function which was used in rte_log_dump().
> > >>>
> > >>> The new function rte_log_list_types() is exported in the API
> > >>> for allowing an application to give this info to the user
> > >>> if not exposing the EAL option --log-level.
> > >>> The list of log types cannot include all drivers if not linked in the
> > >>> application (shared object plugin case).
> > >>>
> > >>> Signed-off-by: Thomas Monjalon <thomas at monjalon.net>
> > >>> ---
> > >>>  lib/librte_eal/common/eal_common_log.c     | 24 +++++++++---
> > >>>  lib/librte_eal/common/eal_common_options.c | 44 +++++++++++++++-------
> > >>>  lib/librte_eal/common/eal_log.h            |  5 +++
> > >>>  lib/librte_eal/include/rte_log.h           | 11 ++++++
> > >>>  lib/librte_eal/version.map                 |  3 ++
> > >>>  5 files changed, 69 insertions(+), 18 deletions(-)
> > >>>  
> > > <snip>  
> > >>> @@ -1274,6 +1286,11 @@ eal_parse_log_level(const char *arg)
> > >>>  	char *str, *level;
> > >>>  	int priority;
> > >>>  
> > >>> +	if (strcmp(arg, "help") == 0) {  
> > >>
> > >> So I think the convention is to support both "?" and "help".
> > >> Qemu does this at least. 
> > >>  
> > > I've seen "/?" used for help on windows binaries, but "-?" not so much in the
> > > linux world, where --help (and often -h for short) seem to be the standard.
> > >   
> > 
> > This is slightly different - it is where you are looking to return a list of valid 
> > values for a parameter. So for instance in qemu mentioned above 
> > 
> >  ~ > qemu-system-x86_64 -cpu ? | head -n 10  
> 
> "?" is a special character.
> In my zsh, I need to quote it to avoid globbing parsing,
> so I'm not a fan.
> 
> I will let you extend the syntax in a separate patch :)
> 
> 

Also '?' is used by getopt to match unknown option. So qemu might just be
doing that as unintended side effect of any unknown option