30 Jun
2009
30 Jun
'09
4:58 p.m.
2009/6/30 Daniel Santos <javatroubadour(a)yahoo.com>om>:
Some pointers are getting used prior to
initialization. It would appear that the current compilers are initializing them to zero
or we've been lucky.
No, the C standard specifies that these are initialized to NULL, since
they have static storage duration.
4 Jul
4 Jul
7:03 p.m.
New subject: server/fd.c: Prevent using uninitialized pointers
Henri Verbeet wrote:
2009/6/30 Daniel Santos
<javatroubadour(a)yahoo.com>om>:
We are assuming that the c compilers are following the standard. I was
told a long time ago, 1994 to be exact, that if we want to insure that a
variable has a certain value to initialize it to that value. This
applies if we want a zero or a NULL.
[code]
int a = 0;
char b = NULL;
bool c = TRUE;
[/code]
Without this, we cannot assume anything.
James McKenzie
Some pointers are getting used prior to
initialization. It would appear that the current compilers are initializing them to zero
or we've been lucky.
No, the C standard specifies that these are initialized to NULL, since
they have static storage duration.
8:23 p.m.
New subject: server/fd.c: Prevent using uninitialized pointers
James McKenzie wrote:
[code]
int a = 0;
char b = NULL;
bool c = TRUE;
[/code]
Without this, we cannot assume anything.
Static variables are different. They are always initialized to 0. In your
example you show regular variables only. Their initial value is not defined.
Vitaliy.
9:22 p.m.
New subject: server/fd.c: Prevent using uninitialized pointers
Vitaliy Margolen wrote:
James McKenzie wrote:
Correct. I was making the assumption that the discussion was not about
static variables. Static variables are always initialized:
static int a;
will be zero
static char b;
will be NULL
static bool c;
will be set to false (0) unless zero is defined as TRUE.
However, if you want a particular result, it is always best to
initialize the variables you are going to use.
James McKenzie
[code]
int a = 0;
char b = NULL;
bool c = TRUE;
[/code]
Without this, we cannot assume anything.
Static variables are different. They are always initialized to 0. In your
example you show regular variables only. Their initial value is not defined.
5 Jul
5 Jul
12:32 a.m.
New subject: server/fd.c: Prevent using uninitialized pointers
On 07/04/2009 11:22 PM, James McKenzie wrote:
Vitaliy Margolen wrote:
or, more precisely (pedantically) NUL or '\0' (which just happens to be the same
as NULL [all bits set to 0] on most (all?) architectures IIRC)
Frédéric
James McKenzie wrote:
Correct. I was making the assumption that the discussion was not about
static variables. Static variables are always initialized:
static int a;
will be zero
static char b;
will be NULL [code]
int a = 0;
char b = NULL;
bool c = TRUE;
[/code]
Without this, we cannot assume anything.
Static variables are different. They are always initialized to 0. In your
example you show regular variables only. Their initial value is not defined.
9:31 p.m.
New subject: server/fd.c: Prevent using uninitialized pointers
2009/7/4 Vitaliy Margolen <wine-devel(a)kievinfo.com>om>:
Static variables are different. They are always
initialized to 0. In your
Yes, although perhaps it should be noted that in this
particular case
the static storage duration is due to these being global variables,
rather than the static keyword which just specifies internal linking
here. (I.e., if they had external linking the pointers would still be
initialized to NULL.)
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5 comments
4 participants
participants (4)
-
Frédéric Delanoy -
Henri Verbeet -
James McKenzie -
Vitaliy Margolen