A sound program

1. # Include <fcntl. h>
2. # Include <stdio. h>
3. # Include <stdlib. h>
4. # Include <string. h>
5. # Include <unistd. h>
6. # Include <sys/IOCTL. h>
7. # Include <sys/types. h>
8. # Include <Linux/KD. h>
10. /* Set the default value */
11. # Define default_freq 10000/* set an appropriate frequency */
12. # Define default_length 1000/* 200 microseconds. The audible length is measured in microseconds */
13. # Define default_reps 5/* No repeated voices by default */
14. # Define default_delay 500/* in microseconds */
15. /* Define a structure to store the required data */
16. Typedef struct
17. {
18. Int freq;/* the expected output frequency, in Hz */
19. Int length;/* audible length, in microseconds */
20. Int reps;/* repeated times */
21. Int delay;/* Two audible intervals, in microseconds */
22. } Beep_parms_t;
23. /* Print the help information and exit */
24. Void usage_bail (const char * executable_name)
25. {
26. Printf ("Usage:/n/T % s [-F frequency] [-l length] [-r reps] [-D delay]/n", executable_name );
27. Exit (1 );
28. }
29. /* Analyze the running parameters, which have the following meanings: * "-F <frequency value in Hz>" * "-l <audible duration in milliseconds>" * "-r <repeated times> "*" -d <Interval Duration in milliseconds> "*/
30. Void parse_command_line (char ** argv, beep_parms_t * result)
31. {
32. Char * arg0 = * (argv ++ );
33. While (* argv)
34. {
35. If (! Strcmp (* argv, "-F "))
36. {/* Frequency */
37. Int freq = atoi (* (++ argv ));
38. If (freq <= 0) | (freq> 10000 ))
39. {
40. Fprintf (stderr, "Bad parameter: frequency must be from 1 .. 10000/N ");
41. Exit (1 );
42. }
43. Else {
44. Result-> freq = freq; argv ++;
45. }
46. }
47. Else if (! Strcmp (* argv, "-l "))
48. {/* Duration */
49. Int length = atoi (* (++ argv ));
50. If (length <0)
51. {
52. Fprintf (stderr, "Bad parameter: length must be> = 0/N ");
53. Exit (1 );
54. }
55. Else {
56. Result-> length = length; argv ++;
57. }
58. }
59. Else if (! Strcmp (* argv, "-R "))
60. {/* Repeated times */
61. Int reps = atoi (* (++ argv ));
62. If (REPS <0)
63. {
64. Fprintf (stderr, "Bad parameter: reps must be> = 0/N ");
65. Exit (1 );
66. } Else
67. {
68. Result-> reps = reps; argv ++;
69. }
70. }
71. Else if (! Strcmp (* argv, "-d "))
72. {/* Latency */
73. Int delay = atoi (* (++ argv ));
74. If (delay <0)
75. {
76. Fprintf (stderr, "Bad parameter: delay must be> = 0/N ");
77. Exit (1 );
78. } Else {
79. Result-> delay = delay; argv ++;
80. }
81. } Else {
82. Fprintf (stderr, "Bad parameter: % s/n", * argv );
83. Usage_bail (arg0 );
84. }
85. }
86. }
88. Int main (INT argc, char ** argv)
89. {
90. Int console_fd; int I;/* loop counter * // * set the voice parameter to the default value */
91. Beep_parms_t parms = {default_freq, default_length, default_reps, default_delay };
92. /* Analyze parameters. If possible, update the audible parameters */
93. Parse_command_line (argv, & parms );
95. /* Open the console and terminate the program if it fails */
96. If (console_fd = open ("/dev/DSP", o_wronly) =-1)
97. {
98. Fprintf (stderr, "failed to open console./N ");
99. Perror ("open ");
100. Exit (1 );
101. }
103. /* Start to let the speaker speak */
104. For (I = 0; I <parms. reps; I ++)
105. {/* Do not know where the number 1190000 comes from */
106. Int magical_fairy_number = 1190000/parms. freq;
108. IOCTL (console_fd, kiocsound, magical_fairy_number );
109. /* Start voice */
110. Usleep (1000 * parms. Length);/* Wait ...*/
111. IOCTL (console_fd, kiocsound, 0 );
112. /* Stop the speaker */
113. Usleep (1000 * parms. Delay);/* Wait ...*/
114. }/* Replay */
115. Return exit_success;
116. }