声卡的设备文件在哪里？如何用C播放

Question

在 中/dev，我只找到/dev/console，而不是/dev/dsp，/dev/audio等，这是朋友告诉我的Linux中声卡的设备文件。

现在，我想在 Ubuntu 14.04 中使用 C 播放音乐并更改音量。这是我的程序，但我失败了。我想知道如何以正确的方式控制声音设备。

 #include <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 #include <sys/ioctl.h>
 #include <sys/types.h>
 #include <linux/kd.h>
/* set default value */
 #define DEFAULT_FREQ 440 /*set freq */
 #define DEFAULT_LENGTH 1000 /*200 ms*/
 #define DEFAULT_REPS 1 /* no repeat by default */
 #define DEFAULT_DELAY 100 /* by ms*/
/* define a struct to save data*/
typedef struct {
    int freq; /* Hz */
    int length; /* duration */
    int reps; /* repeat times */
    int delay; /* the interval */
} beep_parms_t;
/* print the help message and exit */
void usage_bail ( const char *executable_name ) {
    printf ( "Usage: \n \t%s [-f frequency] [-l length] [-r reps] [-d delay] \n ",
    executable_name );
    exit(1);
}
/* analysis the args, the meanings are:
* "-f < the freq by Hz >"
* "-l < duration by ms >"
* "-r < repeat times >"
* "-d < the interval by ms >"
*/
void parse_command_line(char **argv, beep_parms_t *result) {
    char *arg0 = *(argv++);
    while ( *argv ) {
        if ( !strcmp( *argv,"-f" )) { /*freq*/
            int freq = atoi ( *( ++argv ) ); 
            if ( ( freq <= 0 ) || ( freq > 10000 ) ) {
                fprintf ( stderr, "Bad parameter: frequency must be from 1..10000\n" );
                exit (1) ;
            } else {
                result->freq = freq;
                argv++; 
            }
        } else if ( ! strcmp ( *argv, "-l" ) ) { /*duration*/
            int length = atoi ( *(++argv ) );
            if (length < 0) {
                fprintf(stderr, "Bad parameter: length must be >= 0\n");
                exit(1);
            } else {
                result->length = length;
                argv++;
            } 
        } else if (!strcmp(*argv, "-r")) { /*repeat times*/
            int reps = atoi(*(++argv));
            if (reps < 0) {
                fprintf(stderr, "Bad parameter: reps must be >= 0\n");
                exit(1);
            } else {
                result->reps = reps;
                argv++;
            } 
        } else if (!strcmp(*argv, "-d")) { /* delay */
            int delay = atoi(*(++argv));
            if (delay < 0) {
                fprintf(stderr, "Bad parameter: delay must be >= 0\n");
                exit(1);
            } else {
                result->delay = delay;
                argv++;
            } 
        } else {
            fprintf(stderr, "Bad parameter: %s\n", *argv);
            usage_bail(arg0);
        }
    }
}
int main(int argc, char **argv) {
    int console_fd;
    int i; /* loop counter */
    /* default value */
    beep_parms_t parms = {DEFAULT_FREQ, DEFAULT_LENGTH, DEFAULT_REPS, 
        DEFAULT_DELAY};
    /* analysis the args */
    parse_command_line(argv, &parms);
    printf("after param\n");
    /* open the device file*/
    if ( ( console_fd = open ( "/dev/console", O_WRONLY ) ) == -1 ) {
        fprintf(stderr, "Failed to open console.\n");
        perror("open");
        exit(1);
    }
    /* start to play */
    for (i = 0; i < parms.reps; i++) {
        int magical_fairy_number = 1190000/parms.freq;
        ioctl(console_fd, KIOCSOUND, magical_fairy_number); /* start */
        usleep(1000*parms.length); /*wait... */
        ioctl(console_fd, KIOCSOUND, 0); /* stop */
        usleep(1000*parms.delay); /* wait... */
    } /* repeat */
    return EXIT_SUCCESS;
}