do nothing capture with openal

do_nothing_openal.c

#include <AL/al.h>
#include <AL/alc.h>
#include <stdio.h>
#include <string.h>
#include <signal.h>

#define BUFF_SIZE 44100
#define FREQUENCY 44100

int running;

// just stop with ctrl+c
void stoprunning(int signum)
{
    running = 0;
}

int main(void)
{
    const ALCchar *device_list;
    const ALCchar *device_default;

    ALCdevice *device;

    ALCubyte buffer[BUFF_SIZE];
    ALCint sample;

    int i, j, max_devices, selected_device;

    alGetError();

    // get devices informations
    device_default = alcGetString(NULL, ALC_CAPTURE_DEFAULT_DEVICE_SPECIFIER);
    device_list = alcGetString(NULL, ALC_CAPTURE_DEVICE_SPECIFIER);

    max_devices = 0;

    // list devices and mark default with '**'
    for ( i=0, j=0; device_list[i] != '\0'; i++)
    {
        printf("%d - %s", j, &device_list[i]);

        if (strcmp(&device_list[i], device_default) == 0)
        {
            puts(" **");
        }
        else
        {
            puts("");
        }

        for ( ; device_list[i] != '\0'; i++);

        max_devices++;
        j++;
    }

    // let select device
    puts("\nselect your device");
    scanf("%d", &selected_device);

    // valid selected device
    if ( selected_device < 0 || selected_device >= max_devices)
    {
        printf("invalid device selection!\n");
        return 1;
    }

    // position on selected device
    for ( i=0, j=0; j<=selected_device; j++)
    {
        device_default = &device_list[i];
        for ( ; device_list[i] != '\0'; i++);
        i++;
    }

    // output device name confirmation
    printf("\n%s selected\n", device_default);

    // open device with 44100 frequence and same buffersize
    device = alcCaptureOpenDevice(device_default, FREQUENCY, AL_FORMAT_MONO8, BUFF_SIZE);
    if ( device == 0 )
    {
        printf("could not open device, with error: %d\n", alGetError());
        return 1;
    }

    alcCaptureStart(device);

    // attach signal handler
    running = 1;
    signal(SIGINT, stoprunning);

    puts("\nstarting...");
    while ( running )
    {
        // check how much was read
        alcGetIntegerv(device, ALC_CAPTURE_SAMPLES, (ALCsizei) sizeof(ALCint), &sample);
        
        // copy internal framebuffer to external
        alcCaptureSamples(device, (ALCvoid*) buffer, sample);

        // do something with buffer
    }

    alcCaptureStop(device);
    alcCaptureCloseDevice(device);
    printf("finalizing...");

    return 0;
}