Re: [dpdk-dev] [PATCH v2] devtools: check %l format specifier

[Thomas Monjalon <thomas@monjalon.net>]

21/05/2021 14:01, Ferruh Yigit:
> On 5/19/2021 8:24 PM, Thomas Monjalon wrote:
> > From: Ferruh Yigit <ferruh.yigit@intel.com>
> > 
> > %lx or %llx tend to be wrong for 32-bit platform
> > if used for fixed size variable like uint64_t.
> > A checkpatch warning will avoid this common mistake.
> > 
> > Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
> > Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
> > ---
> > v2: proposal to reword the message and comment
> > ---
> > +	# check %l or %ll format specifier
> > +	awk -v FOLDERS='lib drivers app examples' \
> > +		-v EXPRESSIONS='%ll*[xud]' \
> > +		-v RET_ON_FAIL=1 \
> > +		-v MESSAGE='Using %l format, should it be %PRI*64?' \
> > +		-f $(dirname $(readlink -f $0))/check-forbidden-tokens.awk \
> > +		"$1" || res=1
> 
> Using the %l or %ll format specifier is correct when the variable type is "long
> int" or "long long int", it is only wrong if the variable type is fixed size
> like 'unit64_t'.
> 
> My concern is above warning log may cause people change the correct usage.
> 
> That was why I tried to make wording less strict, more like a reminder to double
> check the usage.

This is a question now: "should it be", why do you think it is strict?

> If we can check that format specifier is used for 'unit64_t' variable, that will
> be the best solution but that is very hard to do.
> Should we add a little more information to the message to prevent false hit on
> the correct usage?

Your message was:
"Please check %llx usage which tends to be wrong most of the times"
Mine:
"Using %l format, should it be %PRI*64?"

Trying to give more info about what can be wrong while keeping short:

"Using %l format, is it a long variable or should it be %PRI*64?