Re: [PATCH 1/2] maint.mk: Split long argument lists

[Roman Bolshakov]

On Sun, Dec 02, 2018 at 01:26:52PM +0100, Bruno Haible wrote:
> Roman Bolshakov wrote:
> > But then we will need to correct calculation of VC_ARG_MAX. We can take
> > formulae from [2]:
> > expr `getconf ARG_MAX` - `env|wc -c` - `env|egrep '^[^ ]+='|wc -l` \* 4 - 
> > 2048
> 
> This formula assumes that a pointer in the 'environ' array is 4 bytes long.
> On 64-bit platforms it surely is 8 bytes long.
> 
> More generally, I find this formula too fragile. It assumes so many things.
> I would prefer a formula which does not attempt to produce the highest 
> possible
> value, but makes less assumptions. How about
>   expr `getconf ARG_MAX` / 2
> ?
> 

Hi Bruno,

I agree the command knows too much. I wasn't sure if it's important for
someone if we use maximum possible value.

I've found some prior art in computing max effective argument length in
libtool (3/4 of ARG_MAX on GNU/BSD):
http://git.savannah.gnu.org/cgit/libtool.git/tree/m4/libtool.m4#n1682

If someone needs the value, probably it's worth to move the computation
from libtool to gnulib.

Thank you,
Roman