On Fri, May 22, 2020 at 11:58:23AM +0200, Thomas Vigouroux wrote:
Quoting Ivan Tham (2020-05-22 10:52:21)
I believe you may need to convert it to double before division and round the
volume. My dwms have something similar:
return smprintf("%d", (int) rint((double) (val - min) /
(double) (max - min) * 100));
https://github.com/pickfire/dwms/blob/c2038a4104f4f80aa6f675821c62e87ccfe48bed/dwms.c#L213-L241
Actually, multiplying before might avoid floating point computation and only
uses integer computation.
Thanks for your answer and suggestion !
Here is an updated patch :
diff --git a/components/volume.c b/components/volume.c
index 61cec90..f2e5b70 100644
--- a/components/volume.c
+++ b/components/volume.c
@@ -72,6 +72,57 @@
return bprintf("%d", m ? 0 : v * 100 / 255);
}
+#elif defined(__linux__)
+ #include <alsa/asoundlib.h>
+ #include <alsa/mixer.h>
+
+ const char *
+ vol_perc(const char * card)
+ {
+ long minv, maxv, outvol;
+ snd_mixer_t* handle;
+ snd_mixer_elem_t* elem;
+ snd_mixer_selem_id_t* sid;
+
+ static const char* mix_name = "Master";
+ static int mix_index = 0;
+
+ snd_mixer_selem_id_alloca(&sid);
+
+ /* sets simple-mixer index and name */
+ snd_mixer_selem_id_set_index(sid, mix_index);
+ snd_mixer_selem_id_set_name(sid, mix_name);
+
+ if (snd_mixer_open(&handle, 0) < 0)
+ return NULL;
+ if (snd_mixer_attach(handle, card) < 0) {
+ snd_mixer_close(handle);
+ return NULL;
+ }
There seemed to be a lot of repeated patterns, why not use goto like other C
projects to handle failure?
+ if (snd_mixer_selem_register(handle, NULL, NULL) < 0) {
+ snd_mixer_close(handle);
+ return NULL;
+ }
+ if (snd_mixer_load(handle) < 0) {
+ snd_mixer_close(handle);
+ return NULL;
+ }
+ elem = snd_mixer_find_selem(handle, sid);
+ if (!elem) {
+ snd_mixer_close(handle);
+ return NULL;
+ }
+
+ snd_mixer_selem_get_playback_volume_range(elem, &minv, &maxv);
+
+ if(snd_mixer_selem_get_playback_volume(elem, 0, &outvol) < 0) {
+ snd_mixer_close(handle);
+ return NULL;
+ }
+
+ snd_mixer_close(handle);
+ return bprintf("%ld", (100 * (outvol - minv)) / (maxv - minv));
If I recall correctly, it is something like:
const char* buf = NULL;
...
if (failure)
goto error;
...
buf = bprintf("%ld", (100 * (outvol - minv)) / (maxv - minv));
error:
snd_mixer_close(handle);
return buf;
Not sure if it is better like the other code I have seen but I think it reduces
the code duplication.
+ }
#else
#include <sys/soundcard.h>
diff --git a/config.def.h b/config.def.h
index e06be66..af2197c 100644
--- a/config.def.h
+++ b/config.def.h
@@ -58,6 +58,7 @@ static const char unknown_str[] = "n/a";
* uptime system uptime NULL
* username username of current user NULL
* vol_perc OSS/ALSA volume in percent mixer file (/dev/mixer)
+ * sound card name on
Linux (default)
* wifi_perc WiFi signal in percent interface name (wlan0)
* wifi_essid WiFi ESSID interface name (wlan0)
*/
diff --git a/config.mk b/config.mk
index 3b32b7c..cd2a234 100644
--- a/config.mk
+++ b/config.mk
@@ -14,7 +14,7 @@ X11LIB = /usr/X11R6/lib
CPPFLAGS = -I$(X11INC) -D_DEFAULT_SOURCE
CFLAGS = -std=c99 -pedantic -Wall -Wextra -Os
LDFLAGS = -L$(X11LIB) -s
-LDLIBS = -lX11
+LDLIBS = -lX11 -lasound
# compiler and linker
CC = cc
