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ALSA: Introduce snd_BUG_ON() macro

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Introduced snd_BUG_ON() macro as a replacement of snd_assert() macro.
snd_assert() is pretty ugly as it has the control flow in its argument.
OTOH, snd_BUG_ON() behaves like a normal conditional, thus it's much
easier to read the flow.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
This commit is contained in:
Takashi Iwai 2008-08-08 17:06:01 +02:00 committed by Jaroslav Kysela
parent 3caf8c080e
commit 5ef03460a6
2 changed files with 45 additions and 0 deletions
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41
Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl
View File

@ -6173,6 +6173,47 @@ struct _snd_pcm_runtime {
When no debug flag is set, this macro is ignored.
</para>
</section>
<section id="useful-functions-snd-bug-on">
<title><function>snd_BUG_ON()</function></title>
<para>
<function>snd_BUG_ON()</function> macro is similar with
<function>WARN_ON()</function> macro. For example,
<informalexample>
<programlisting>
<![CDATA[
snd_BUG_ON(!pointer);
]]>
</programlisting>
</informalexample>
or it can be used as the condition,
<informalexample>
<programlisting>
<![CDATA[
if (snd_BUG_ON(non_zero_is_bug))
return -EINVAL;
]]>
</programlisting>
</informalexample>
</para>
<para>
The macro takes an conditional expression to evaluate.
When <constant>CONFIG_SND_DEBUG</constant>, is set, the
expression is actually evaluated. If it's non-zero, it shows
the warning message such as
<computeroutput>BUG? (xxx)</computeroutput>
normally followed by stack trace. It returns the evaluated
value.
When no <constant>CONFIG_SND_DEBUG</constant> is set, this
macro always returns zero.
</para>
</section>
</chapter>

4
include/sound/core.h
View File

@ -28,6 +28,7 @@
#include <linux/rwsem.h> /* struct rw_semaphore */
#include <linux/pm.h> /* pm_message_t */
#include <linux/device.h>
#include <linux/stringify.h>
/* number of supported soundcards */
#ifdef CONFIG_SND_DYNAMIC_MINORS
@ -405,11 +406,14 @@ void snd_verbose_printd(const char *file, int line, const char *format, ...)
dump_stack(); \
} while (0)
#define snd_BUG_ON(cond) WARN((cond), "BUG? (%s)\n", __stringify(cond))
#else /* !CONFIG_SND_DEBUG */
#define snd_printd(fmt, args...) /* nothing */
#define snd_assert(expr, args...) (void)(expr)
#define snd_BUG() /* nothing */
#define snd_BUG_ON(cond) ({/*(void)(cond);*/ 0;}) /* always false */
#endif /* CONFIG_SND_DEBUG */