Prosty Player Na Alsie (c++)

[alpin19]

Witam

 

Na podstawie alsowego tutoriala napisałem prostego player'a:

#include <stdio.h>
    #include <stdlib.h>
    #include <alsa/asoundlib.h>
          
    main (int argc, char *argv[])
    {
        int i;
        int err;
        short buf[128];
        snd_pcm_t *playback_handle;
        snd_pcm_hw_params_t *hw_params;
    
        if ((err = snd_pcm_open (&playback_handle, argv[1], SND_PCM_STREAM_PLAYBACK, 0)) < 0) {
            fprintf (stderr, "cannot open audio device %s (%s)\n", 
                 argv[1],
                 snd_strerror (err));
            exit (1);
        }
           
        if ((err = snd_pcm_hw_params_malloc (&hw_params)) < 0) {
            fprintf (stderr, "cannot allocate hardware parameter structure (%s)\n",
                 snd_strerror (err));
            exit (1);
        }
                 
        if ((err = snd_pcm_hw_params_any (playback_handle, hw_params)) < 0) {
            fprintf (stderr, "cannot initialize hardware parameter structure (%s)\n",
                 snd_strerror (err));
            exit (1);
        }
    
        if ((err = snd_pcm_hw_params_set_access (playback_handle, hw_params, SND_PCM_ACCESS_RW_INTERLEAVED)) < 0) {
            fprintf (stderr, "cannot set access type (%s)\n",
                 snd_strerror (err));
            exit (1);
        }
    
        if ((err = snd_pcm_hw_params_set_format (playback_handle, hw_params, SND_PCM_FORMAT_S16_LE)) < 0) {
            fprintf (stderr, "cannot set sample format (%s)\n",
                 snd_strerror (err));
            exit (1);
        }
    
        if ((err = snd_pcm_hw_params_set_rate_near (playback_handle, hw_params, 44100, 0)) < 0) {
            fprintf (stderr, "cannot set sample rate (%s)\n",
                 snd_strerror (err));
            exit (1);
        }
    
        if ((err = snd_pcm_hw_params_set_channels (playback_handle, hw_params, 2)) < 0) {
            fprintf (stderr, "cannot set channel count (%s)\n",
                 snd_strerror (err));
            exit (1);
        }
    
        if ((err = snd_pcm_hw_params (playback_handle, hw_params)) < 0) {
            fprintf (stderr, "cannot set parameters (%s)\n",
                 snd_strerror (err));
            exit (1);
        }
    
        snd_pcm_hw_params_free (hw_params);
    
        if ((err = snd_pcm_prepare (playback_handle)) < 0) {
            fprintf (stderr, "cannot prepare audio interface for use (%s)\n",
                 snd_strerror (err));
            exit (1);
        }
    
        for (i = 0; i < 10; ++i) {
            if ((err = snd_pcm_writei (playback_handle, buf, 128)) != 128) {
                fprintf (stderr, "write to audio interface failed (%s)\n",
                     snd_strerror (err));
                exit (1);
            }
        }
    
        snd_pcm_close (playback_handle);
        exit (0);
    }

 

Kiedy próbuję go kompilować dostaję taki wynik:

 

[root@zanegi mpeeg]# g++ player.cpp -o player
player.cpp:69:2: warning: no newline at end of file
player.cpp: In function ‘int main(int, char**)’:
player.cpp:13: error: expected initializer before ‘if’
player.cpp:19: error: ‘hw_params’ was not declared in this scope
player.cpp:24: error: ‘hw_params’ was not declared in this scope
player.cpp:29: error: ‘hw_params’ was not declared in this scope
player.cpp:32: error: expected `;' before ‘exit’
player.cpp:34: error: ‘hw_params’ was not declared in this scope
player.cpp:39: error: ‘hw_params’ was not declared in this scope
player.cpp:44: error: ‘hw_params’ was not declared in this scope
player.cpp:50: error: ‘hw_params’ was not declared in this scope
player.cpp:66: error: expected `;' before numeric constant
player.cpp:66: warning: statement is a reference, not call, to function ‘exit’

 

 

[Daniello]

Popraw błędy w tych linijkach co ci kompilator zapodał, a poza tym to masz warna za tak długi listing. Używa się do tak długich listingów Codeboxa

[@Sorror]

To nie jest C++, nie nadawaj mylących tytułów swoim wątkom.

[Gość amdfanatyk]

ogolnie jest taka przykra sprawa bo nie ma czegos jak main(int argc, char ** argv).

[lszk]

Musisz dołączyć odpowiednią bibliotekę przy kompilacji. Zapodaj linka do tego kursu, tam powinno być. Do tego zmień main na int main, w linii 44 zamień 44100 na (unsigned int*)44100.

[Gość amdfanatyk]

w linii 44 zamień 44100 na (unsigned int*)44100.

 

co to by mialo byc? z tego co wiem nie ma zmiennych o nazwach liczbowych, zatem dlaczego 44100 chcesz rzutowac na wskazanie na uint? chyba, ze 44100 to adres jest.

[lszk]

invalid conversion from int to unsigned int*

 

Pluje się przy 3-cim argumencie funkcji snd_pcm_hw_params_set_rate_near()

[Gość amdfanatyk]

ludzie wezcie sobie jakis program najpierw napiszcie bo takie pierdoly jak tu wypisujecie to sie plakac chce i rece opadaja, jakies podstawy c/c++ by sie przydaly, wiedziec co to wskazanie, referencja;

 

unsigned int var = 1234;
unsigned int * pVar = &var;