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  1. // my_alsa_mute_change.c
  2.  
  3. //------------------------------------------------------------------------------
  4. // my_alsa_mute_change : alsaのmuteのon/offを逆転させる
  5. //  1. amixer get Master |grep -v channel | grep -i playback | grep -i left
  6. //      で
  7. //     "  Front Left: Playback 22282 [34%] [on]"
  8. //     "  Front Left: Playback 22282 [34%] [off]"
  9. //      いずれかが返ってくるので、これで現在のミュートon/offを判定し
  10. //  2. 現在on なら、amixer set Master mute
  11. //         offなら、amixer set Master unmute
  12. //     を実行する
  13. //------------------------------------------------------------------------------
  14. #include <stdio.h>
  15. #include <stdlib.h>
  16. #include <string.h>
  17. #include <unistd.h>     // for unlink();
  18.  
  19. #define TEMP_FILE       "/tmp/my_alsa_mute_change.tmp"
  20. #define FIND_PATTERN_1  "\%] ["
  21. #define FIND_PATTERN_2  "]"
  22.  
  23. typedef enum _MUTE_MODE {
  24.     MM_On,
  25.     MM_Off,
  26.     MM_Unknown,
  27. } MUTE_MODE;
  28.  
  29. MUTE_MODE get_mute_mode(void)
  30. {
  31.     FILE *fp;
  32.     char b[256];
  33.     char *p, *pp;
  34.     MUTE_MODE res_mode;
  35.  
  36.     // 初期化
  37.     fp = NULL;
  38.     res_mode = MM_Unknown;
  39.  
  40.     // 現在の状態を b[]; に取得
  41.     system("amixer get Master | grep -v channel | grep -i playback | grep -i left > " TEMP_FILE);
  42.     if (NULL == (fp = fopen(TEMP_FILE, "r"))) {
  43.         goto END__get_mute_mode;
  44.     }
  45.     if (NULL == fgets(b, sizeof(b), fp)) {
  46.         goto END__get_mute_mode;
  47.     }
  48.     fclose(fp);
  49.     fp = NULL;
  50.     unlink(TEMP_FILE);
  51.     // "  Front Left: Playback 22282 [34%] [on]"
  52.     // "  Front Left: Playback 22282 [34%] [off]"
  53.     // から、on/off文字列を p に抽出
  54.     if (NULL == (p = strstr(b, FIND_PATTERN_1))) {
  55.         goto END__get_mute_mode;
  56.     }
  57.     p += strlen(FIND_PATTERN_1);
  58.     if (NULL == (pp = strstr(p, FIND_PATTERN_2))) {
  59.         goto END__get_mute_mode;
  60.     }
  61.     *pp = '\0';
  62.     // on/off判定
  63.     if (0 == strcasecmp(p, "on")) {
  64.         res_mode = MM_On;
  65.     } else if (0 == strcasecmp(p, "off")) {
  66.         res_mode = MM_Off;
  67.     } else {
  68.         goto END__get_mute_mode;
  69.     }
  70.  
  71. END__get_mute_mode:
  72.     if (fp) {
  73.         fclose(fp);
  74.         fp = NULL;
  75.     }
  76.     return res_mode;
  77. }
  78.  
  79. void set_mute_mode(MUTE_MODE mm)
  80. {
  81.     switch (mm) {
  82.     case MM_On:
  83.         system("amixer set Master unmute");
  84.         break;
  85.     case MM_Off:
  86.         system("amixer set Master mute");
  87.         break;
  88.     default:
  89.         break;
  90.     }
  91. }
  92.  
  93. int main()
  94. {
  95.     MUTE_MODE mm;
  96.  
  97.     mm = get_mute_mode();
  98.     switch (mm) {
  99.     case MM_On:
  100.         set_mute_mode(MM_Off);
  101.         break;
  102.     case MM_Off:
  103.         set_mute_mode(MM_On);
  104.         break;
  105.     default:
  106.         fprintf(stderr, "Mute mode unknown!!\n");
  107.         return 1;
  108.     }
  109.  
  110.     return 0;
  111. }
  112.  
  113. // End of my_alsa_mute_change.c
  114.  
Runtime error #stdin #stdout #stderr 0s 3824KB
comments (?)
stdin 
Standard input is empty
stdout 
Standard output is empty
stderr 
sh: amixer: not found
sh: cannot create /tmp/my_alsa_mute_change.tmp: Permission denied
Mute mode unknown!!
https://ideone.com/DRTtrU
language:
C (gcc 8.3)
created:
10 years ago
visibility:
secret

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