Re: [PATCH 1/2] dir.c: fix uninitialized memory warning

From: Nguyen Thai Ngoc Duy <pclouds@gmail.com>
Date: Sep 16, 2010, 23:26 UTC
Message-ID: <AANLkTik1X0i-OYZCxokw-W3Kt+vEDtBvFeCwQU3q40ap@mail.gmail.com>
In-Reply-To: <AANLkTim4SiuX=aWLeYXKpgvD+Nh1trH8qgf3V36iVa9w@mail.gmail.com>

2010/9/17 Ævar Arnfjörð Bjarmason <avarab@gmail.com>:

Show 25 quoted lines

> On Thu, Sep 16, 2010 at 20:53, Pat Notz <patnotz@gmail.com> wrote:
>> GCC 4.4.4 on MacOS warns about potential use of uninitialized memory.
>>
>> Signed-off-by: Pat Notz <patnotz@gmail.com>
>> ---
>>  dir.c |    2 +-
>>  1 files changed, 1 insertions(+), 1 deletions(-)
>>
>> diff --git a/dir.c b/dir.c
>> index 133f472..d1e5e5e 100644
>> --- a/dir.c
>> +++ b/dir.c
>> @@ -232,7 +232,7 @@ int add_excludes_from_file_to_list(const char *fname,
>>  {
>>        struct stat st;
>>        int fd, i;
>> -       size_t size;
>> +       size_t size = 0;
>>        char *buf, *entry;
>
> What does the GCC warning say exactl? I.e. what line does it complain
> about?
>
> Maybe this is a logic error introduced in v1.7.0-rc0~25^2? I haven't
> checked.

I don't see any case that "size" can be used uninitialized. Maybe the compiler was confused by

if (!check_index ||
    (buf = read_skip_worktree_file_from_index(fname, &size)) == NULL)
        return -1;

I wouldn't hurt though to initialize it early, even just to stop the compiler from complaining.

-- 
Duy