Help me modify my Sound Server

Ok, I have a "sound server" written in SDL, heres its code:

sndserv.h:

Code:

---

#include <SDL/SDL.h>
#include <stdio.h>
#include <stdlib.h>
#define null NULL

#define MAX_PLAYING_SOUNDS 10
#define VOLUME_PER_SOUND SDL_MIX_MAXVOLUME / 2

//Desired Audio Specs
#define FREQUENCY        44100;
#define FORMAT                AUDIO_S16
#define SAMPLES                4096
#define CHANNELS        2
#define CALLBACK        AudioCallback
#define USERDATA        NULL

static SDL_AudioSpec desired, obtained;

typedef struct Sound_s {
        Uint8 *samples;
        Uint32 length;
} Sound, *Sound_p;

typedef struct playing_s {
        int active;
        Sound_p sound;
        Uint32 position;
} playing_t, *playing_p;

static playing_t playing[MAX_PLAYING_SOUNDS];

void AudioCallback(void *user_data, Uint8 *audio, int length){
        int i;
       
        memset(audio, 0, length);
       
        for (i = 0; i < MAX_PLAYING_SOUNDS; i++){
                if (playing[i].active){
                        Uint8 *sound_buf;
                        Uint32 sound_len;
                       
                        sound_buf = playing[i].sound->samples;
                        sound_buf += playing[i].position;
                       
                        if ((playing[i].position + length) > playing[i].sound->length){
                                sound_len = playing[i].sound->length - playing[i].position;
                        } else {
                                sound_len = length;
                        }
                       
                        SDL_MixAudio(audio, sound_buf, sound_len, VOLUME_PER_SOUND);
                       
                        playing[i].position += length;
                       
                        if (playing[i].position >= playing[i].sound->length){
                                playing[i].active = 0;
                        }
                }
        }
}

int LoadSound(char *filename, Sound_p sound){
        SDL_AudioSpec *spec = &obtained;
        SDL_AudioCVT cvt;
        SDL_AudioSpec loaded;
        Uint8 *new_buf;
       
        if (SDL_LoadWAV(filename, &loaded, &sound->samples, &sound->length) == null){
                printf("Unable to load sound: %s\n", SDL_GetError());
                return 1;
        }
       
        if (SDL_BuildAudioCVT(&cvt, loaded.format, loaded.channels, loaded.freq, spec->format, spec->channels, spec->freq) < 0){
                printf("Unable to convert sound: %s\n", SDL_GetError());
                return 1;
        }
       
        cvt.len = sound->length;
        new_buf = (Uint8 *)malloc(cvt.len * cvt.len_mult);
        if (new_buf == null){
                printf("Out of memory!\n");
                SDL_FreeWAV(sound->samples);
                return 1;
        }
       
        memcpy(new_buf, sound->samples, sound->length);
       
        cvt.buf = new_buf;
        if (SDL_ConvertAudio(&cvt) < 0){
                printf("Audio conversion error:%s\n", SDL_GetError());
                free(new_buf);
                SDL_FreeWAV(sound->samples);
                return 1;
        }
       
        SDL_FreeWAV(sound->samples);
        sound->samples = new_buf;
        sound->length = sound->length * cvt.len_mult;
       
        printf("%s was loaded and converted successfully.\n", filename);
        return 0;
}

void ClearPlayingSounds(void){
        int i;
        for (i = 0; i < MAX_PLAYING_SOUNDS; i++){
                playing[i].active = 0;
        }
}

int PlaySound(Sound_p sound){
        int i;
        for (i = 0; i < MAX_PLAYING_SOUNDS; i++){
                if (playing[i].active == 0){
                        break;
                }
        }
       
        if (i == MAX_PLAYING_SOUNDS){
                return 1;
        }
       
        SDL_LockAudio();
        playing[i].active = 1;
        playing[i].sound = sound;
        playing[i].position = 0;
        SDL_UnlockAudio();
       
        return 0;
}


int sndserv_init(){
        desired.freq = FREQUENCY;
        desired.format = FORMAT;
        desired.samples = SAMPLES;
        desired.channels = CHANNELS;
        desired.callback = CALLBACK;
        desired.userdata = USERDATA;
       
        if (SDL_OpenAudio(&desired, &obtained) < 0){
                printf("Unable to open Audio Device");
                return 1;
        }
       
        atexit(SDL_CloseAudio);
       
        ClearPlayingSounds();
       
        SDL_PauseAudio(0);
}

int sndserv_end(){
        SDL_PauseAudio(1);
        SDL_LockAudio();
}

int FreeSound(Sound_p snd){
        SDL_LockAudio();
        free(snd->samples);
        SDL_UnlockAudio();
}

---

ok heres how a simple example works:

sndtest.c:

Code:

---

#include <SDL/SDL.h>
#include "sndserv.h"

int main(int argc, char *argv[]){
        Sound explosion;
       
        SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO);
       
        atexit(SDL_Quit);
       
        sndserv_init();
       
        LoadSound("sound/explosion.wav", &explosion);
       
        PlaySound(&explosion);
       
        SDL_Delay(5000);
       
        sndserv_end();
       
        FreeSound(&explosion);
       
        return 0;
}

---

As you can see you load sounds with LoadSound

How could I modify the function so that LoadSound works like this:

explosion = LoadSound("sound/explosion.wav");

Any help would be greatly appreaciated.

> explosion = LoadSound("sound/explosion.wav");
The first question is why are you ignoring the return result at present, and how do you propose to return error values with this new interface.

I was ignoring the result because this was a simple demo of the "server" and because I forgot. :D

I plan on giving an error by returning a null pointer.

> #define FREQUENCY 44100;
This is very poor - remove the trailing ;

Heh, typo demon. Thanks