c - ALSA programming: how to stop immediately -

i building audio app playback , stop features. function playaudio() playback, stopaudio() stop. expected file format wav.

the main implementation of playaudio() below:

playaudio() { ... ...     int err = snd_pcm_open(&handle, "default", snd_pcm_stream_playback, 0);     if ( err < 0 )     {        printf("scm open failed: %s\n", snd_strerror(err));                        exit(err);     }      while ( 0 < numofframes) {         ... ...         ssize_t frames = snd_pcm_writei(handle, &buffer[0], periodsize);         ... ...     }      snd_pcm_drain(handle);     snd_pcm_close(handle); }  stopaudio() {     snd_pcm_drop( m_handle ); } 

while audio playing back, program blocked @ line of snd_pcm_drain(handle); until playback completion. during period, expect stop audio play. action click stop button on ui , call snd_pcm_drop( m_handle ) finally. voice stopped, programm running still staying @ line of snd_pcm_drain(handle) untils several seconds later play time of played audio file.

my question is: how make snd_pcm_drain's waiting on immmediately once stop action performed? if not, there other way implement immediate stop keeping playaudio function waiting playback completion?

thank much.