Prev: C++0x support in compilers for embedded systems
Next: friend function and storage specifier
From: A. McKenney on 26 Apr 2010 09:10
I'm running into a problem with my C++ compiler.
I don't know whether what I am doing is illegal,
or it's a compiler bug.

My understanding is that you can initialize
a static const integer in the class declaration.
But my compiler (Sun studio11) doesn't allow it
for size_t, which I always assumed was an integer
type. Is initialization in the class declaration
limited to only certain integral types?

The following code compiles OK
if I comment out the #define:

#define USE_SIZE_T
class A
{
public:
#ifdef USE_SIZE_T
static const size_t s = 10;
#else
static const int s = 10;
#endif
char array[s];
};


#ifdef USE_SIZE_T
const size_t A::s;
#else
const int A::s;
#endif


If I leave it in, it seems to think that size_t is
a variable name.

--
[ See http://www.gotw.ca/resources/clcm.htm for info about ]
[ comp.lang.c++.moderated. First time posters: Do this! ]

From: Öö Tiib on 26 Apr 2010 22:53
On Apr 27, 3:10 am, "A. McKenney" <alan_mckenn...(a)yahoo.com> wrote:
> I'm running into a problem with my C++ compiler.
> I don't know whether what I am doing is illegal,
> or it's a compiler bug.
>
> My understanding is that you can initialize
> a static const integer in the class declaration.
> But my compiler (Sun studio11) doesn't allow it
> for size_t, which I always assumed was an integer
> type. Is initialization in the class declaration
> limited to only certain integral types?
>
> The following code compiles OK
> if I comment out the #define:
>
> #define USE_SIZE_T
> class A
> {
> public:
> #ifdef USE_SIZE_T
> static const size_t s = 10;
> #else
> static const int s = 10;
> #endif
> char array[s];
> };
>
> #ifdef USE_SIZE_T
> const size_t A::s;
> #else
> const int A::s;
> #endif
>
> If I leave it in, it seems to think that size_t is
> a variable name.

size_t is yes synonym for implementation defined unsigned integral
type, so it should work. However i believe that a program is ill-
formed if you use identifier size_t without including <cstddef> that
introduces that name. Problem may be is there since your code example
does not show that you include it.


--
[ See http://www.gotw.ca/resources/clcm.htm for info about ]
[ comp.lang.c++.moderated. First time posters: Do this! ]

From: Jd on 26 Apr 2010 23:01
On Apr 27, 9:10 am, "A. McKenney" <alan_mckenn...(a)yahoo.com> wrote:
> I'm running into a problem with my C++ compiler.
> I don't know whether what I am doing is illegal,
> or it's a compiler bug.
>
> My understanding is that you can initialize
> a static const integer in the class declaration.
> But my compiler (Sun studio11) doesn't allow it
> for size_t, which I always assumed was an integer
> type. Is initialization in the class declaration
> limited to only certain integral types?
>
> The following code compiles OK
> if I comment out the #define:
>
> #define USE_SIZE_T
> class A
> {
> public:
> #ifdef USE_SIZE_T
> static const size_t s = 10;
> #else
> static const int s = 10;
> #endif
> char array[s];
> };
>
> #ifdef USE_SIZE_T
> const size_t A::s;
> #else
> const int A::s;
> #endif
>
> If I leave it in, it seems to think that size_t is
> a variable name.
>

Did you include the header that defines "size_t"

#include <stddef.h> OR
#include <stdlib.h>

Jd


--
[ See http://www.gotw.ca/resources/clcm.htm for info about ]
[ comp.lang.c++.moderated. First time posters: Do this! ]

From: Paul Bibbings on 26 Apr 2010 23:02
"A. McKenney" <alan_mckenney1(a)yahoo.com> writes:

>
> The following code compiles OK
> if I comment out the #define:
>
> #define USE_SIZE_T
> class A
> {
> public:
> #ifdef USE_SIZE_T
> static const size_t s = 10;
> #else
> static const int s = 10;
> #endif
> char array[s];
> };
>
>
> #ifdef USE_SIZE_T
> const size_t A::s;
> #else
> const int A::s;
> #endif
>
>
> If I leave it in, it seems to think that size_t is
> a variable name.

Have you made size_t available to your program with #include <cstddef>,
or some other include that brings it in?

Regards

Paul Bibbings

--
[ See http://www.gotw.ca/resources/clcm.htm for info about ]
[ comp.lang.c++.moderated. First time posters: Do this! ]

From: Daniel Krügler on 26 Apr 2010 23:59
On 27 Apr., 02:10, "A. McKenney" <alan_mckenn...(a)yahoo.com> wrote:
> I'm running into a problem with my C++ compiler.
> I don't know whether what I am doing is illegal,
> or it's a compiler bug.

This is a compiler bug, see below.

> My understanding is that you can initialize
> a static const integer in the class declaration.
> But my compiler (Sun studio11) doesn't allow it
> for size_t, which I always assumed was an integer
> type. Is initialization in the class declaration
> limited to only certain integral types?

Referring to the C++ standard 14882:2003(E) the answer
is clear, [class.static.data]/4 says:

"If a static data member is of const integral or const
enumeration type, its declaration in the class definition
can specify a constant-initializer which shall be an
integral constant expression (5.19)."

size_t is defined in <stddef.h> and in <cstddef> both
being required to be the same type. I have only a recent
C99 standard available, which says that size_t is an
"unsigned integer type" (7.17).

Finally, as of [basic.fundamental]/7 of above quoted C++
standard we have:

"Types bool, char, wchar_t, and the signed and unsigned
integer types are collectively called integral types. A
synonym for integral type is integer type.[..]"

Thus, I see no way of an alternative reading that would
exclude std::size_t from the list of valid types that
allow for in-class initialization syntax.

HTH & Greetings from Bremen,

Daniel Kr�gler





--
[ See http://www.gotw.ca/resources/clcm.htm for info about ]
[ comp.lang.c++.moderated. First time posters: Do this! ]

 |  Next  |  Last
Pages: 1 2
Prev: C++0x support in compilers for embedded systems
Next: friend function and storage specifier