Re: truncate.c fails to compile on make distcheck

[Pádraig Brady]

Rather than relying on code inspection to find places
where signed ints would be erroneously promoted to unsigned,
I went looking for a gcc option to automatically detect this.
It's -Wsign-compare which is automatically included in -Wextra.
Note it might be good to add to README-hacking to run configure
with the CFLAGS="-Wall -Wextra" options?

So turning that on didn't show any more bugs, but I've attached
a patch to fix the warnings in a couple of places where the
code was ambiguous.

There is still a warning given by the ST_BLKSIZE() macro in
src/system.h where it compares a blksize_t which is long int
on my system, to SIZE_MAX. Perhaps a cast to (size_t) is
required there to confirm the intent?

thanks,
Pádraig.

>From 9af2fe570111c4073588293facdea87cf9151e55 Mon Sep 17 00:00:00 2001
From: =?utf-8?q?P=C3=A1draig=20Brady?= <address@hidden>
Date: Fri, 27 Jun 2008 08:38:42 +0100
Subject: [PATCH] truncate: Silence -Wsign-compare errors

src/truncate.c: Cast signed to unsigned to
confirm intent which will silence -Wsign-compare errors
---
 src/truncate.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/truncate.c b/src/truncate.c
index 02d4102..fd321c6 100644
--- a/src/truncate.c
+++ b/src/truncate.c
@@ -189,9 +189,9 @@ do_ftruncate (int fd, char const *fname, off_t ssize, 
rel_mode_t rel_mode)
         }
 
       if (rel_mode == rm_min)
-        nsize = MAX (fsize, ssize);
+        nsize = MAX (fsize, (uintmax_t) ssize);
       else if (rel_mode == rm_max)
-        nsize = MIN (fsize, ssize);
+        nsize = MIN (fsize, (uintmax_t) ssize);
       else if (rel_mode == rm_rdn)
         /* 0..ssize-1 -> 0 */
         nsize = (fsize / ssize) * ssize;
-- 
1.5.3.6