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extern char *optarg;

extern int optind, opterr, optopt;
 

           const char *optstring,

           const struct option *longopts, int *longindex);

optstring is a string containing the legitimate option characters. If such a character is followed by a colon, the option requires an argument, so getopt() places a pointer to the following text in the same argv-element, or the text of the following argv-element, in optarg. Two colons mean an option takes an optional arg; if there is text in the current argv-element (i.e., in the same word as the option name itself, for example, "-oarg"), then it is returned in optarg, otherwise optarg is set to zero. This is a GNU extension. If optstring contains W followed by a semicolon, then -W foo is treated as the long option --foo. (The -W option is reserved by POSIX.2 for implementation extensions.) This behavior is a GNU extension, not available with libraries before glibc 2. 
 

err = snd_output_stdio_attach(&output, stdout, 0);

if (err < 0) {

        printf("Output failed: %s\n", snd_strerror(err));

        return 0;

}
 

void showstat(snd_pcm_t *handle, size_t frames)

{

        int err;

        snd_pcm_status_t *status;

        snd_pcm_status_alloca(&status);

        if ((err = snd_pcm_status(handle, status)) < 0) {

                printf("Stream status error: %s\n", snd_strerror(err));

                exit(0);

        }

        printf("*** frames = %li ***\n", (long)frames);

        snd_pcm_status_dump(status, output);