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authorTakashi Iwai <tiwai@suse.de>2008-08-08 11:06:01 -0400
committerJaroslav Kysela <perex@perex.cz>2008-08-13 05:46:32 -0400
commit5ef03460a6ffc1d3ee6b6f2abc6765d3e224cf89 (patch)
tree1947acad9b61fa80567fa1dd20c5b8c65ff8a46d /Documentation/sound
parent3caf8c080ef0bd0ccdc20bb57b150b6e40a86fd3 (diff)
ALSA: Introduce snd_BUG_ON() macro
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>
Diffstat (limited to 'Documentation/sound')
-rw-r--r--Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl41
1 files changed, 41 insertions, 0 deletions
diff --git a/Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl b/Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl
index e13c4e67029f..df699e4323ef 100644
--- a/Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl
+++ b/Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl
@@ -6173,6 +6173,47 @@ struct _snd_pcm_runtime {
6173 When no debug flag is set, this macro is ignored. 6173 When no debug flag is set, this macro is ignored.
6174 </para> 6174 </para>
6175 </section> 6175 </section>
6176
6177 <section id="useful-functions-snd-bug-on">
6178 <title><function>snd_BUG_ON()</function></title>
6179 <para>
6180 <function>snd_BUG_ON()</function> macro is similar with
6181 <function>WARN_ON()</function> macro. For example,
6182
6183 <informalexample>
6184 <programlisting>
6185<![CDATA[
6186 snd_BUG_ON(!pointer);
6187]]>
6188 </programlisting>
6189 </informalexample>
6190
6191 or it can be used as the condition,
6192 <informalexample>
6193 <programlisting>
6194<![CDATA[
6195 if (snd_BUG_ON(non_zero_is_bug))
6196 return -EINVAL;
6197]]>
6198 </programlisting>
6199 </informalexample>
6200
6201 </para>
6202
6203 <para>
6204 The macro takes an conditional expression to evaluate.
6205 When <constant>CONFIG_SND_DEBUG</constant>, is set, the
6206 expression is actually evaluated. If it's non-zero, it shows
6207 the warning message such as
6208 <computeroutput>BUG? (xxx)</computeroutput>
6209 normally followed by stack trace. It returns the evaluated
6210 value.
6211 When no <constant>CONFIG_SND_DEBUG</constant> is set, this
6212 macro always returns zero.
6213 </para>
6214
6215 </section>
6216
6176 </chapter> 6217 </chapter>
6177 6218
6178 6219