[parted-devel] Problem with Linux "3.0"

[Jim Meyering]

H. Peter Anvin wrote:
> On 06/07/2011 08:53 AM, Jim Meyering wrote:
>> Yes, just like the original code.
>> The reason I prefer not to ignore the return value is to avoid
>> warnings from static analyzers.
>
> Declare it (void) explicitly then...

With some versions of gcc, the (void) cast does not suffice
to avoid the warn-unused-result warnings.
That's why the gnulib "ignore-value" module came to be.
So we can do this:

    ignore_value (sscanf (...));

But that (like the void cast) is pretty ugly.
But using two sscanf calls with the associated logic is even uglier,
so I'll go for your change after all.

However, I don't want to ignore the return value.

How about the patch below?
I left your name on it.
Let me know if that's ok.

>From 0b6cd440ac094cefd791dba9d19d112aafd09fdf Mon Sep 17 00:00:00 2001
From: "H. Peter Anvin" <hpa at zytor.com>
Date: Tue, 7 Jun 2011 18:03:14 +0200
Subject: [PATCH] libparted: simplify kernel version-parsing logic

* libparted/arch/linux.c: (_get_linux_version): Simplify and add
an assertion.
---
 libparted/arch/linux.c |   15 +++++----------
 1 files changed, 5 insertions(+), 10 deletions(-)

diff --git a/libparted/arch/linux.c b/libparted/arch/linux.c
index 111816c..bfe2982 100644
--- a/libparted/arch/linux.c
+++ b/libparted/arch/linux.c
@@ -601,22 +601,17 @@ _get_linux_version ()
         static int kver = -1;

         struct utsname uts;
-        int major;
-        int minor;
-        int teeny;
+        int major = 0;
+        int minor = 0;
+        int teeny = 0;

         if (kver != -1)
                 return kver;

         if (uname (&uts))
                 return kver = 0;
-        if (sscanf (uts.release, "%u.%u.%u", &major, &minor, &teeny) == 3)
-                ; /* ok */
-        else if (sscanf (uts.release, "%u.%u", &major, &minor) == 2)
-                teeny = 0;
-        else
-                return kver = 0;
-
+        int n = sscanf (uts.release, "%u.%u.%u", &major, &minor, &teeny);
+        assert (n == 2 || n == 3);
         return kver = KERNEL_VERSION (major, minor, teeny);
 }

--
1.7.6.rc0.293.g40857