On 15/03/2021 15:59, Stephen Hemminger wrote:

On Mon, 15 Mar 2021 11:52:13 +0100
Thomas Monjalon [off-list ref] wrote:

quoted

15/03/2021 11:42, Kinsella, Ray:

quoted

On 15/03/2021 10:31, Bruce Richardson wrote:  

quoted

On Mon, Mar 15, 2021 at 10:19:47AM +0000, Kinsella, Ray wrote:  

quoted

On 12/03/2021 18:17, Thomas Monjalon wrote:  

quoted

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 <redacted>
---
 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>  

quoted

quoted

@@ -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

for other unknowns it explicitly complains ... 

~ > qemu-system-x86_64 -cpu unknown
Unable to init server: Could not connect: Connection refused
qemu-system-x86_64: unable to find CPU model 'unknown