number of arguments zargs use

number of arguments zargs use

[Motoi Washida]

Hi all,

I use zargs. It is good when I want to use long arguments. But it uses 
too small number of arguments at a time for me.

This tries to get size of arguments allowed. I don't know this is 
portable enough, but it seems to work for me.

Index: zargs
===================================================================
RCS file: /cvsroot/zsh/zsh/Functions/Misc/zargs,v
retrieving revision 1.3
diff -d -u -r1.3 zargs
--- zargs	4 Sep 2002 06:28:37 -0000	1.3
+++ zargs	30 Oct 2004 13:54:47 -0000
@@ -213,7 +213,21 @@
      fi
  fi

-s=${${s##-(s|-max-chars(=|))}:-20480}
+s=${s##-(s|-max-chars(=|))}
+
+if (( !s ))
+then
+    local argmax envvars
+    argmax="$({command getconf ARG_MAX ||
+	command sysctl -n kern.argmax} 2>/dev/null)"
+    if (( argmax ))
+    then
+        envvars="$(builtin typeset -x)"
+        s=$(( argmax - ( ${#${(f)envvars}} + ${#envvars} + 2048 ) ))
+    else
+        s=-20480
+    fi
+fi
  l=${${l##-(l|-max-lines(=|))}:-${${l[1]:+1}:-$ARGC}}

  # Everything has to be in a subshell just in case of backgrounding 
jobs,

--
Motoi Washida

Re: number of arguments zargs use

[Bart Schaefer]

On Sat, 30 Oct 2004, Motoi Washida wrote:

> This tries to get size of arguments allowed. I don't know this is 
> portable enough, but it seems to work for me.

This set me off wandering down the road to Obfuscatory ...

s=${${s##-(s|-max-chars(=|))}:-$(((s=$({command getconf ARG_MAX ||
    command sysctl -n kern.argmax || echo 0} 2>/dev/null))?
    (s-=${#$(builtin typeset +x)}+2048):20480))}

That would be equivalent to, though significantly less readable than, 
your patch, except that there is a bug in your patch:

> +    else
> +        s=-20480
> +    fi

That should be "s=20480", not -20480.  You'd never want a negative number
of characters.

Re: number of arguments zargs use

[Motoi Washida]

Hi Bart,

> This set me off wandering down the road to Obfuscatory ...
>
> s=${${s##-(s|-max-chars(=|))}:-$(((s=$({command getconf ARG_MAX ||
>     command sysctl -n kern.argmax || echo 0} 2>/dev/null))?
>     (s-=${#$(builtin typeset +x)}+2048):20480))}
I don't mind which way is used.

>> +    else
>> +        s=-20480
>> +    fi
Opps, sorry.

Thanks!
--
Motoi Washida

Re: number of arguments zargs use

[Bart Schaefer]

On Sat, 30 Oct 2004, Bart Schaefer wrote:

> s=${${s##-(s|-max-chars(=|))}:-$(((s=$({command getconf ARG_MAX ||
>     command sysctl -n kern.argmax || echo 0} 2>/dev/null))?
>     (s-=${#$(builtin typeset +x)}+2048):20480))}

Just in case anyone tries this, there's a typo: +x should be -x.