ssize_t snd_pcm_format_size(snd_pcm_format_t format, size_t samples);
const unsigned char *snd_pcm_format_silence_64(snd_pcm_format_t format);
int snd_pcm_format_set_silence(snd_pcm_format_t format, void *buf, unsigned int frames);
-snd_pcm_format_t snd_pcm_build_linear_format(int width, int unsignd, int big_endian);
+snd_pcm_format_t snd_pcm_build_linear_format(int width, int unsigned, int big_endian);
void snd_pcm_set_ops(struct snd_pcm * pcm, int direction, struct snd_pcm_ops *ops);
void snd_pcm_set_sync(struct snd_pcm_substream *substream);