Re: dfa.c:in_coll_range z/OS fixes

[Jim Meyering]

Aharon Robbins wrote:
> Hi. My z/OS maintainer indicates that in_coll_range() doesn't compile
> there. He suggests the following patch:
>
> *** dfa.c.orig Fri Apr  2 06:00:20 2010
> --- dfa.c Fri Apr  2 05:59:38 2010
> ***************
> *** 408,414 ****
> --- 408,419 ----
>   static int
>   in_coll_range (char ch, char from, char to)
>   {
> + #ifdef ZOS_USS
> +   char c[6] = { 0, 0, 0, 0, 0, 0 };
> +   c[0] = from; c[2] = ch; c[4] = to;
> + #else
>     char c[6] = { from, 0, ch, 0, to, 0 };
> + #endif
>     return strcoll (&c[0], &c[2]) <= 0 && strcoll (&c[2], &c[4]) <= 0;
>   }
>
> I rather prefer this one, since it's straightforward and clear:

And since it avoids not only in-function, but system-specific
(contrary to autoconf's feature-test philosophy) #if tests.

> Index: dfa.c
> ===================================================================
> RCS file: /d/mongo/cvsrep/gawk-stable/dfa.c,v
> retrieving revision 1.29
> diff -u -r1.29 dfa.c
> --- dfa.c     2 Apr 2010 09:33:41 -0000       1.29
> +++ dfa.c     4 Apr 2010 12:29:47 -0000
> @@ -408,7 +501,10 @@
>  static int
>  in_coll_range (char ch, char from, char to)
>  {
> -  char c[6] = { from, 0, ch, 0, to, 0 };
> +  char c[6] = { 0, 0, 0, 0, 0, 0 };
> +  c[0] = from;
> +  c[2] = ch;
> +  c[4] = to;
>    return strcoll (&c[0], &c[2]) <= 0 && strcoll (&c[2], &c[4]) <= 0;
>  }
>
> Please let me know if either of these is acceptable.

I prefer to avoid even the semblance of dead stores
for the odd-numbered elements.  I've committed the following
change on a private-for-now "old-compilers" branch.
I'll see how much trouble it is to carry this one change
through the upcoming development.  If the branch survives and
grows, I may eventually publish it.

>From 4aeebc7febb4ccd49ecffd0181159c0dd866642c Mon Sep 17 00:00:00 2001
From: Jim Meyering <address@hidden>
Date: Tue, 6 Apr 2010 20:59:10 +0200
Subject: [PATCH] avoid C99 auto initializer syntax

* src/dfa.c (in_coll_range): Initialize explicitly.  For z/OS.
---
 src/dfa.c |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/src/dfa.c b/src/dfa.c
index ca32b66..ef878f2 100644
--- a/src/dfa.c
+++ b/src/dfa.c
@@ -375,7 +375,13 @@ static unsigned char const *buf_end;       /* reference to 
end in dfaexec().  */
 static int
 in_coll_range (char ch, char from, char to)
 {
-  char c[6] = { from, 0, ch, 0, to, 0 };
+  char c[6];
+  c[0] = from;
+  c[1] = 0;
+  c[2] = ch;
+  c[3] = 0;
+  c[4] = to;
+  c[5] = 0;
   return strcoll (&c[0], &c[2]) <= 0 && strcoll (&c[2], &c[4]) <= 0;
 }

--
1.7.0.4.552.gc303