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Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/DocBook/writing-an-alsa-driver.tmpl | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/Documentation/DocBook/writing-an-alsa-driver.tmpl b/Documentation/DocBook/writing-an-alsa-driver.tmpl index 784793df81ed..84ef6a90131c 100644 --- a/Documentation/DocBook/writing-an-alsa-driver.tmpl +++ b/Documentation/DocBook/writing-an-alsa-driver.tmpl @@ -3658,6 +3658,29 @@ struct _snd_pcm_runtime { </para> <para> + The above callback can be simplified with a helper function, + <function>snd_ctl_enum_info</function>. The final code + looks like below. + (You can pass ARRAY_SIZE(texts) instead of 4 in the third + argument; it's a matter of taste.) + + <informalexample> + <programlisting> +<![CDATA[ + static int snd_myctl_enum_info(struct snd_kcontrol *kcontrol, + struct snd_ctl_elem_info *uinfo) + { + static char *texts[4] = { + "First", "Second", "Third", "Fourth" + }; + return snd_ctl_enum_info(uinfo, 1, 4, texts); + } +]]> + </programlisting> + </informalexample> + </para> + + <para> Some common info callbacks are available for your convenience: <function>snd_ctl_boolean_mono_info()</function> and <function>snd_ctl_boolean_stereo_info()</function>. |