Remove 0/NULL global variable assignment in mixer-test.c and pcm-test.c
Signed-off-by: Nikola Z. Ivanov zlatistiv@gmail.com --- tools/testing/selftests/alsa/mixer-test.c | 8 ++++---- tools/testing/selftests/alsa/pcm-test.c | 8 ++++---- 2 files changed, 8 insertions(+), 8 deletions(-)
diff --git a/tools/testing/selftests/alsa/mixer-test.c b/tools/testing/selftests/alsa/mixer-test.c index 2a4b2662035e..e113dafa5c24 100644 --- a/tools/testing/selftests/alsa/mixer-test.c +++ b/tools/testing/selftests/alsa/mixer-test.c @@ -53,10 +53,10 @@ struct ctl_data { struct ctl_data *next; };
-int num_cards = 0; -int num_controls = 0; -struct card_data *card_list = NULL; -struct ctl_data *ctl_list = NULL; +int num_cards; +int num_controls; +struct card_data *card_list; +struct ctl_data *ctl_list;
static void find_controls(void) { diff --git a/tools/testing/selftests/alsa/pcm-test.c b/tools/testing/selftests/alsa/pcm-test.c index dbd7c222ce93..ce92548670c8 100644 --- a/tools/testing/selftests/alsa/pcm-test.c +++ b/tools/testing/selftests/alsa/pcm-test.c @@ -30,7 +30,7 @@ struct card_data { struct card_data *next; };
-struct card_data *card_list = NULL; +struct card_data *card_list;
struct pcm_data { snd_pcm_t *handle; @@ -43,10 +43,10 @@ struct pcm_data { struct pcm_data *next; };
-struct pcm_data *pcm_list = NULL; +struct pcm_data *pcm_list;
-int num_missing = 0; -struct pcm_data *pcm_missing = NULL; +int num_missing; +struct pcm_data *pcm_missing;
snd_config_t *default_pcm_config;
On Thu, Aug 21, 2025 at 11:01:32PM +0300, Nikola Z. Ivanov wrote:
Remove 0/NULL global variable assignment in mixer-test.c and pcm-test.c
Why?
--- a/tools/testing/selftests/alsa/mixer-test.c +++ b/tools/testing/selftests/alsa/mixer-test.c @@ -53,10 +53,10 @@ struct ctl_data { struct ctl_data *next; }; -int num_cards = 0; -int num_controls = 0; -struct card_data *card_list = NULL; -struct ctl_data *ctl_list = NULL; +int num_cards; +int num_controls; +struct card_data *card_list; +struct ctl_data *ctl_list;
Nothing now sets initial values for these variables so they all have undefined values which is buggy. The code is relying on the default values.
On Thu, Aug 21, 2025 at 09:49:29PM +0100, Mark Brown wrote:
On Thu, Aug 21, 2025 at 11:01:32PM +0300, Nikola Z. Ivanov wrote:
Remove 0/NULL global variable assignment in mixer-test.c and pcm-test.c
Why?
--- a/tools/testing/selftests/alsa/mixer-test.c +++ b/tools/testing/selftests/alsa/mixer-test.c @@ -53,10 +53,10 @@ struct ctl_data { struct ctl_data *next; };
-int num_cards = 0; -int num_controls = 0; -struct card_data *card_list = NULL; -struct ctl_data *ctl_list = NULL; +int num_cards; +int num_controls; +struct card_data *card_list; +struct ctl_data *ctl_list;
Nothing now sets initial values for these variables so they all have undefined values which is buggy. The code is relying on the default values.
Checkpatch reports it as an error, it looks to be part of the C standard that all compilers must initialize globals to 0. Though I suppose it helps with readability to see the num_ counters assigned 0.
On Fri, Aug 22, 2025 at 12:17:14AM +0300, Nikola Ivanov wrote:
On Thu, Aug 21, 2025 at 09:49:29PM +0100, Mark Brown wrote:
-int num_cards = 0; -int num_controls = 0; -struct card_data *card_list = NULL; -struct ctl_data *ctl_list = NULL; +int num_cards; +int num_controls; +struct card_data *card_list; +struct ctl_data *ctl_list;
Nothing now sets initial values for these variables so they all have undefined values which is buggy. The code is relying on the default values.
Checkpatch reports it as an error, it looks to be part of the C standard that all compilers must initialize globals to 0. Though I suppose it helps with readability to see the num_ counters assigned 0.
Do you have a reference there, note that these are just plain non-static variables? I wouldn't trust checkpatch for anything that isn't kernel code (and even there it's got issues).
On Thu, Aug 21, 2025 at 10:30:50PM +0100, Mark Brown wrote:
On Fri, Aug 22, 2025 at 12:17:14AM +0300, Nikola Ivanov wrote:
On Thu, Aug 21, 2025 at 09:49:29PM +0100, Mark Brown wrote:
-int num_cards = 0; -int num_controls = 0; -struct card_data *card_list = NULL; -struct ctl_data *ctl_list = NULL; +int num_cards; +int num_controls; +struct card_data *card_list; +struct ctl_data *ctl_list;
Nothing now sets initial values for these variables so they all have undefined values which is buggy. The code is relying on the default values.
Checkpatch reports it as an error, it looks to be part of the C standard that all compilers must initialize globals to 0. Though I suppose it helps with readability to see the num_ counters assigned 0.
Do you have a reference there, note that these are just plain non-static variables? I wouldn't trust checkpatch for anything that isn't kernel code (and even there it's got issues).
This is what it says in the C99/C11/C18/C23 drafts I found:
If an object that has automatic storage duration is not initialized explicitly, its value is indeterminate. If an object that has static or thread storage duration is not initialized explicitly, then: — if it has pointer type, it is initialized to a null pointer; — if it has arithmetic type, it is initialized to (positive or unsigned) zero;
"static or thread storage" referring to variables declared at global scope (regardless of static keyword) as well as those inside function scope defined with static keyword.
Since as you said checkpatch.pl is mostly intended for kernel code (which I was not aware of) this patch is probably not desired. In case it still is I can add quote to the draft and link it in the patch.
On Fri, Aug 22, 2025 at 01:57:05AM +0300, Nikola Z. Ivanov wrote:
On Thu, Aug 21, 2025 at 10:30:50PM +0100, Mark Brown wrote:
Do you have a reference there, note that these are just plain non-static variables? I wouldn't trust checkpatch for anything that isn't kernel code (and even there it's got issues).
This is what it says in the C99/C11/C18/C23 drafts I found:
...
Since as you said checkpatch.pl is mostly intended for kernel code (which I was not aware of) this patch is probably not desired. In case it still is I can add quote to the draft and link it in the patch.
No, it's fine - thanks for checking the reference. I suspected this might be something specific to how the kernel is linked:
Reviewed-by: Mark Brown broonie@kernel.org
On Thu, 21 Aug 2025 22:01:32 +0200, Nikola Z. Ivanov wrote:
Remove 0/NULL global variable assignment in mixer-test.c and pcm-test.c
Signed-off-by: Nikola Z. Ivanov zlatistiv@gmail.com
Applied now. Thanks.
Takashi
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Mark Brown -
Nikola Ivanov -
Nikola Z. Ivanov
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Takashi Iwai