Listing all devices open AL does not work - c++

Question

I have found some examples that claims to list all output devices for audio using openAL, however I can only get them to list the currently selected device on OSX (Yosemite, Maverick). I am using a mac and have the default sound card (Built-in Output) as well as an airplay device and some sound flower devices.
(Note: On windows it lists all devices)
I am expecting s = (char *)alcGetString(NULL, ALC_ALL_DEVICES_SPECIFIER); to list at least the default card and the sound flower devices. It returns nothing.
s = (char *)alcGetString(NULL, ALC_DEVICE_SPECIFIER); Returns the currently selected device.
Maybe there is some issue with the devices being virtual? however, selecting soundflower from mac settings as default output first make it show up instead o "Built-in Output". We also tried with an external DAC and got the same behaviour.
list of all available output devices: Built-in Output
list of all available input devices: Built-in Microphone
default output device: Built-in Output
default input device: Built-in Microphone
...
Here is the code:
#ifdef __APPLE__
# include <OpenAL/al.h>
# include <OpenAL/alc.h>
#else
# include <AL/al.h>
# include <AL/alc.h>
# include <AL/alext.h>
#endif
#ifndef AL_VERSION_1_1
# ifdef __APPLE__
# include <OpenAL/altypes.h>
# include <OpenAL/alctypes.h>
#else
# include <AL/altypes.h>
# include <AL/alctypes.h>
# endif
#endif
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <string>
using std::string;
#ifndef ALC_ALL_DEVICES_SPECIFIER
# define ALC_ALL_DEVICES_SPECIFIER 0x1013
#endif
#define MAX_DATA 16
static const int indentation = 4;
static const int maxmimumWidth = 79;
void printExtensions (const char *, char, const char *);
void displayDevices(const char *, const char *);
char *getDeviceName(int, char **);
void testForError(void *, const string&);
void testForALCError(ALCdevice *);
int main(int argc, char **argv)
{
ALCint data[MAX_DATA];
ALCdevice *device = NULL;
ALCcontext *context = NULL;
ALenum error;
char *s;
if (alcIsExtensionPresent(NULL, "ALC_enumeration_EXT") == AL_TRUE)
{
if (alcIsExtensionPresent(NULL, "ALC_enumerate_all_EXT") == AL_FALSE)
s = (char *)alcGetString(NULL, ALC_DEVICE_SPECIFIER);
else
s = (char *)alcGetString(NULL, ALC_ALL_DEVICES_SPECIFIER);
displayDevices("output", s);
s = (char *)alcGetString(NULL, ALC_CAPTURE_DEVICE_SPECIFIER);
displayDevices("input", s);
}
s = getDeviceName(argc, argv);
device = alcOpenDevice(s);
testForError(device, "Audio device not available.");
context = alcCreateContext(device, NULL);
testForError(context, "Unable to create a valid context.");
alcMakeContextCurrent(context);
testForALCError(device);
s = (char *)alcGetString(device, ALC_DEFAULT_DEVICE_SPECIFIER);
printf("default output device: %s\n", s);
testForALCError(device);
error = alcIsExtensionPresent(device, "ALC_EXT_capture");
if (error)
{
s = (char *)alcGetString(device, ALC_CAPTURE_DEFAULT_DEVICE_SPECIFIER);
printf("default input device: %s\n", s);
testForALCError(device);
}
printf("capture support: %s\n", (error) ? "yes" : "no");
alcGetIntegerv(device, ALC_FREQUENCY, 1, data);
printf("mixer frequency: %u hz\n", data[0]);
testForALCError(device);
alcGetIntegerv(device, ALC_REFRESH, 1, data+1);
printf("refresh rate : %u hz\n", data[0]/data[1]);
testForALCError(device);
data[0] = 0;
alcGetIntegerv(device, ALC_MONO_SOURCES, 1, data);
error = alcGetError(device);
if (error == AL_NONE) {
printf("supported sources; mono: %u, ", data[0]);
data[0] = 0;
alcGetIntegerv(device, ALC_STEREO_SOURCES, 1, data);
printf("stereo: %u\n", data[0]);
testForALCError(device);
}
printf("ALC version: ");
alcGetIntegerv(device, ALC_MAJOR_VERSION, 1, data);
printf("%i.", *data);
alcGetIntegerv(device, ALC_MINOR_VERSION, 1, data);
printf("%i\n", *data);
testForALCError(device);
s = (char *)alcGetString(device, ALC_EXTENSIONS);
printExtensions ("ALC extensions", ' ', s);
testForALCError(device);
s = (char *)alGetString(AL_VENDOR);
error = alGetError();
if ((error = alGetError()) != AL_NO_ERROR)
printf("Error #%x: %s\n", error, alGetString(error));
else
printf("OpenAL vendor string: %s\n", s);
s = (char *)alGetString(AL_RENDERER);
if ((error = alGetError()) != AL_NO_ERROR)
printf("Error #%x: %s\n", error, alGetString(error));
else
printf("OpenAL renderer string: %s\n", s);
s = (char *)alGetString(AL_VERSION);
if ((error = alGetError()) != AL_NO_ERROR)
printf("Error #%x: %s\n", error, alGetString(error));
else if (!s)
printf("Quering AL_VERSION returned NULL pointer!\n");
else
printf("OpenAL version string: %s\n", s);
s = (char *)alGetString(AL_EXTENSIONS);
printExtensions ("OpenAL extensions", ' ', s);
testForALCError(device);
/* alut testing mechanism */
context = alcGetCurrentContext();
if (context == NULL)
{
printf("Error: no current context\n");
}
else
{
if (alGetError () != AL_NO_ERROR)
{
printf("Alert: AL error on entry\n");
}
else
{
if (alcGetError (alcGetContextsDevice (context)) != ALC_NO_ERROR)
{
printf("Alert: ALC error on entry\n");
}
}
}
/* end of alut test */
if (alcMakeContextCurrent(NULL) == 0)
printf("alcMakeContextCurrent failed.\n");
device = alcGetContextsDevice(context);
alcDestroyContext(context);
testForALCError(device);
if (alcCloseDevice(device) == 0)
printf("alcCloseDevice failed.\n");
return 0;
}
/* -------------------------------------------------------------------------- */
void
printChar (int c, int *width)
{
putchar (c);
*width = (c == '\n') ? 0 : (*width + 1);
}
void
indent (int *width)
{
int i;
for (i = 0; i < indentation; i++)
{
printChar (' ', width);
}
}
void
printExtensions (const char *header, char separator, const char *extensions)
{
int width = 0, start = 0, end = 0;
printf ("%s:\n", header);
if (extensions == NULL || extensions[0] == '\0')
{
return;
}
indent (&width);
while (1)
{
if (extensions[end] == separator || extensions[end] == '\0')
{
if (width + end - start + 2 > maxmimumWidth)
{
printChar ('\n', &width);
indent (&width);
}
while (start < end)
{
printChar (extensions[start], &width);
start++;
}
if (extensions[end] == '\0')
{
break;
}
start++;
end++;
if (extensions[end] == '\0')
{
break;
}
printChar (',', &width);
printChar (' ', &width);
}
end++;
}
printChar ('\n', &width);
}
char *
getCommandLineOption(int argc, char **argv, const string& option)
{
int slen = option.size();
char *rv = 0;
int i;
for (i=0; i<argc; i++)
{
if (strncmp(argv[i], option.c_str(), slen) == 0)
{
i++;
if (i<argc) rv = argv[i];
}
}
return rv;
}
char *
getDeviceName(int argc, char **argv)
{
static char devname[255];
int len = 255;
char *s;
s = getCommandLineOption(argc, argv, "-d");
if (s)
{
strncpy((char *)&devname, s, len);
len -= strlen(s);
s = getCommandLineOption(argc, argv, "-r");
if (s)
{
strncat((char *)&devname, " on ", len);
len -= 4;
strncat((char *)&devname, s, len);
}
s = (char *)&devname;
}
return s;
}
void
displayDevices(const char *type, const char *list)
{
ALCchar *ptr, *nptr;
ptr = (ALCchar *)list;
printf("list of all available %s devices:\n", type);
if (!list)
{
printf("none\n");
}
else
{
nptr = ptr;
while (*(nptr += strlen(ptr)+1) != 0)
{
printf(" %s\n", ptr);
ptr = nptr;
}
printf(" %s\n", ptr);
}
}
void
testForError(void *p, const string& s)
{
if (p == NULL)
{
printf("\nError: %s\n\n", s.c_str());
exit(-1);
}
}
void
testForALCError(ALCdevice *device)
{
ALenum error;
error = alcGetError(device);
if (error != ALC_NO_ERROR)
printf("\nALC Error %x occurred: %s\n", error, alcGetString(device, error));
}

Answer 1

Just to give you ammunition ... here I compiled your above code and give its console output as executed on linux ubuntu 14.04 g++ (Ubuntu 4.9.1-16ubuntu6) 4.9.1
g++ -o openal_list_audio_devices openal_list_audio_devices.cpp -lopenal
stens#kamchatka ~/Dropbox/Documents/code/c++ λ
stens#kamchatka ~/Dropbox/Documents/code/c++ λ ./openal_list_audio_devices
list of all available output devices:
Built-in Audio Analog Stereo
list of all available input devices:
Built-in Audio Analog Stereo
Monitor of Built-in Audio Analog Stereo
default output device: OpenAL Soft
default input device: Built-in Audio Analog Stereo
capture support: yes
mixer frequency: 44100 hz
refresh rate : 1025 hz
supported sources; mono: 255, stereo: 1
ALC version: 1.1
ALC extensions:
ALC_ENUMERATE_ALL_EXT, ALC_ENUMERATION_EXT, ALC_EXT_CAPTURE,
ALC_EXT_DEDICATED, ALC_EXT_disconnect, ALC_EXT_EFX,
ALC_EXT_thread_local_context, ALC_SOFT_loopback
OpenAL vendor string: OpenAL Community
OpenAL renderer string: OpenAL Soft
OpenAL version string: 1.1 ALSOFT 1.15.1
OpenAL extensions:
AL_EXT_ALAW, AL_EXT_DOUBLE, AL_EXT_EXPONENT_DISTANCE, AL_EXT_FLOAT32,
AL_EXT_IMA4, AL_EXT_LINEAR_DISTANCE, AL_EXT_MCFORMATS, AL_EXT_MULAW,
AL_EXT_MULAW_MCFORMATS, AL_EXT_OFFSET, AL_EXT_source_distance_model,
AL_LOKI_quadriphonic, AL_SOFT_buffer_samples, AL_SOFT_buffer_sub_data,
AL_SOFTX_deferred_updates, AL_SOFT_direct_channels, AL_SOFT_loop_points,
AL_SOFT_source_latency