C++Talk.NET

Cocy · Guest

Hi,

I saw the following code in linux kernel 2.6's code (arch/sparc/lib/
atomic32.c #L17).

spinlock_t __atomic_hash[ATOMIC_HASH_SIZE] = {
[0 ... (ATOMIC_HASH_SIZE-1)] = SPIN_LOCK_UNLOCKED
};

, where
"SPIN_LOCK_UNLOCKED" returns spinlock_t type of struct,
ATOMIC_HASH_SIZE is defined as "4" just above that function in the
same file,
and "spinlock_t" is defined as struct in include/linux/
spinlock_types.h file.

What does the description

[0 ... (ATOMIC_HASH_SIZE-1)] = SPIN_LOCK_UNLOCKED

means exactly?

Is this means initializing anonymous array or something??? like
[0] = SPIN_LOCK_UNLOCKED
[1] = SPIN_LOCK_UNLOCKED
[2] = SPIN_LOCK_UNLOCKED
[3] = SPIN_LOCK_UNLOCKED
???

What I don't understand most is the part "..." in
"[0 ... (ATOMIC_HASH_SIZE-1)]". I've never seen this description in
C before, except for indicating possibility of additional arguments of
a
function (but it's still different from the declaration like
"func(arg1, arg2, ...)" ).

Does anyone know what it is?

Thanks in advance.

Cocy
--
comp.lang.c.moderated - moderation address: clcm (AT) plethora (DOT) net -- you must
have an appropriate newsgroups line in your header for your mail to be seen,
or the newsgroup name in square brackets in the subject line. Sorry.

WillerZ · Guest

It's a GCC extension, which (I believe) operates as you surmised.
--
comp.lang.c.moderated - moderation address: clcm (AT) plethora (DOT) net -- you must
have an appropriate newsgroups line in your header for your mail to be seen,
or the newsgroup name in square brackets in the subject line. Sorry.