我目前正在努力了解電腦或作業系統（這裡是 Linux）接收的鍵盤輸入。
我寫了一個小程式來查看鍵盤上的所有條目，我所能理解的是每個訊息都是 24 個位元組長，每次按鍵似乎都記錄在 3 個這樣的訊息內。
我無法找到一種方法來理解該條目的確切含義。
舉個例子：
- 我的參賽作品
helloworld^C
- 輸出
ffffffd3 31 5d 5d 0 0 0 0 ffffff98 3d c 0 0 0 0 0 4 0 4 0 28 0 7 0
ffffffd3 31 5d 5d 0 0 0 0 ffffff98 3d c 0 0 0 0 0 1 0 1c 0 0 0 0 0
ffffffd3 31 5d 5d 0 0 0 0 ffffff98 3d c 0 0 0 0 0 0 0 0 0 0 0 0 0
ffffffd4 31 5d 5d 0 0 0 0 ffffffc2 5d 9 0 0 0 0 0 4 0 4 0 b 0 7 0
ffffffd4 31 5d 5d 0 0 0 0 ffffffc2 5d 9 0 0 0 0 0 1 0 23 0 1 0 0 0
ffffffd4 31 5d 5d 0 0 0 0 ffffffc2 5d 9 0 0 0 0 0 0 0 0 0 0 0 0 0
ffffffd4 31 5d 5d 0 0 0 0 2c 5b a 0 0 0 0 0 4 0 4 0 b 0 7 0
ffffffd4 31 5d 5d 0 0 0 0 2c 5b a 0 0 0 0 0 1 0 23 0 0 0 0 0
ffffffd4 31 5d 5d 0 0 0 0 2c 5b a 0 0 0 0 0 0 0 0 0 0 0 0 0
ffffffd4 31 5d 5d 0 0 0 0 ffffffc8 ffffffd9 a 0 0 0 0 0 4 0 4 0 8 0 7 0
ffffffd4 31 5d 5d 0 0 0 0 ffffffc8 ffffffd9 a 0 0 0 0 0 1 0 12 0 1 0 0 0
ffffffd4 31 5d 5d 0 0 0 0 ffffffc8 ffffffd9 a 0 0 0 0 0 0 0 0 0 0 0 0 0
ffffffd4 31 5d 5d 0 0 0 0 ffffffe7 16 c 0 0 0 0 0 4 0 4 0 8 0 7 0
ffffffd4 31 5d 5d 0 0 0 0 ffffffe7 16 c 0 0 0 0 0 1 0 12 0 0 0 0 0
ffffffd4 31 5d 5d 0 0 0 0 ffffffe7 16 c 0 0 0 0 0 0 0 0 0 0 0 0 0
ffffffd4 31 5d 5d 0 0 0 0 ffffffac 11 e 0 0 0 0 0 4 0 4 0 f 0 7 0
ffffffd4 31 5d 5d 0 0 0 0 ffffffac 11 e 0 0 0 0 0 1 0 26 0 1 0 0 0
ffffffd4 31 5d 5d 0 0 0 0 ffffffac 11 e 0 0 0 0 0 0 0 0 0 0 0 0 0
ffffffd4 31 5d 5d 0 0 0 0 ffffffc9 ffffffcf e 0 0 0 0 0 4 0 4 0 f 0 7 0
ffffffd4 31 5d 5d 0 0 0 0 ffffffc9 ffffffcf e 0 0 0 0 0 1 0 26 0 0 0 0 0
ffffffd4 31 5d 5d 0 0 0 0 ffffffc9 ffffffcf e 0 0 0 0 0 0 0 0 0 0 0 0 0
ffffffd5 31 5d 5d 0 0 0 0 4c ffffffca 0 0 0 0 0 0 4 0 4 0 f 0 7 0
ffffffd5 31 5d 5d 0 0 0 0 4c ffffffca 0 0 0 0 0 0 1 0 26 0 1 0 0 0
ffffffd5 31 5d 5d 0 0 0 0 4c ffffffca 0 0 0 0 0 0 0 0 0 0 0 0 0 0
ffffffd5 31 5d 5d 0 0 0 0 4d ffffffc7 1 0 0 0 0 0 4 0 4 0 f 0 7 0
ffffffd5 31 5d 5d 0 0 0 0 4d ffffffc7 1 0 0 0 0 0 1 0 26 0 0 0 0 0
ffffffd5 31 5d 5d 0 0 0 0 4d ffffffc7 1 0 0 0 0 0 0 0 0 0 0 0 0 0
ffffffd5 31 5d 5d 0 0 0 0 ffffffab 0 4 0 0 0 0 0 4 0 4 0 12 0 7 0
ffffffd5 31 5d 5d 0 0 0 0 ffffffab 0 4 0 0 0 0 0 1 0 18 0 1 0 0 0
ffffffd5 31 5d 5d 0 0 0 0 ffffffab 0 4 0 0 0 0 0 0 0 0 0 0 0 0 0
ffffffd5 31 5d 5d 0 0 0 0 ffffffb4 fffffffd 4 0 0 0 0 0 4 0 4 0 12 0 7 0
ffffffd5 31 5d 5d 0 0 0 0 ffffffb4 fffffffd 4 0 0 0 0 0 1 0 18 0 0 0 0 0
ffffffd5 31 5d 5d 0 0 0 0 ffffffb4 fffffffd 4 0 0 0 0 0 0 0 0 0 0 0 0 0
ffffffd5 31 5d 5d 0 0 0 0 ffffffbc ffffffbb 5 0 0 0 0 0 4 0 4 0 1a 0 7 0
ffffffd5 31 5d 5d 0 0 0 0 ffffffbc ffffffbb 5 0 0 0 0 0 1 0 11 0 1 0 0 0
ffffffd5 31 5d 5d 0 0 0 0 ffffffbc ffffffbb 5 0 0 0 0 0 0 0 0 0 0 0 0 0
ffffffd5 31 5d 5d 0 0 0 0 ffffffc2 ffffffb8 6 0 0 0 0 0 4 0 4 0 1a 0 7 0
ffffffd5 31 5d 5d 0 0 0 0 ffffffc2 ffffffb8 6 0 0 0 0 0 1 0 11 0 0 0 0 0
ffffffd5 31 5d 5d 0 0 0 0 ffffffc2 ffffffb8 6 0 0 0 0 0 0 0 0 0 0 0 0 0
ffffffd5 31 5d 5d 0 0 0 0 ffffffa8 ffffffb5 7 0 0 0 0 0 4 0 4 0 12 0 7 0
ffffffd5 31 5d 5d 0 0 0 0 ffffffa8 ffffffb5 7 0 0 0 0 0 1 0 18 0 1 0 0 0
ffffffd5 31 5d 5d 0 0 0 0 ffffffa8 ffffffb5 7 0 0 0 0 0 0 0 0 0 0 0 0 0
ffffffd5 31 5d 5d 0 0 0 0 ffffffa3 73 8 0 0 0 0 0 4 0 4 0 12 0 7 0
ffffffd5 31 5d 5d 0 0 0 0 ffffffa3 73 8 0 0 0 0 0 1 0 18 0 0 0 0 0
ffffffd5 31 5d 5d 0 0 0 0 ffffffa3 73 8 0 0 0 0 0 0 0 0 0 0 0 0 0
ffffffd5 31 5d 5d 0 0 0 0 79 70 9 0 0 0 0 0 4 0 4 0 15 0 7 0
ffffffd5 31 5d 5d 0 0 0 0 79 70 9 0 0 0 0 0 1 0 13 0 1 0 0 0
ffffffd5 31 5d 5d 0 0 0 0 79 70 9 0 0 0 0 0 0 0 0 0 0 0 0 0
ffffffd5 31 5d 5d 0 0 0 0 fffffff8 6d a 0 0 0 0 0 4 0 4 0 15 0 7 0
ffffffd5 31 5d 5d 0 0 0 0 fffffff8 6d a 0 0 0 0 0 1 0 13 0 0 0 0 0
ffffffd5 31 5d 5d 0 0 0 0 fffffff8 6d a 0 0 0 0 0 0 0 0 0 0 0 0 0
ffffffd5 31 5d 5d 0 0 0 0 c ffffffec a 0 0 0 0 0 4 0 4 0 f 0 7 0
ffffffd5 31 5d 5d 0 0 0 0 c ffffffec a 0 0 0 0 0 1 0 26 0 1 0 0 0
ffffffd5 31 5d 5d 0 0 0 0 c ffffffec a 0 0 0 0 0 0 0 0 0 0 0 0 0
ffffffd5 31 5d 5d 0 0 0 0 fffffffa ffffffa9 b 0 0 0 0 0 4 0 4 0 f 0 7 0
ffffffd5 31 5d 5d 0 0 0 0 fffffffa ffffffa9 b 0 0 0 0 0 1 0 26 0 0 0 0 0
ffffffd5 31 5d 5d 0 0 0 0 fffffffa ffffffa9 b 0 0 0 0 0 0 0 0 0 0 0 0 0
ffffffd5 31 5d 5d 0 0 0 0 17 ffffffa7 c 0 0 0 0 0 4 0 4 0 7 0 7 0
ffffffd5 31 5d 5d 0 0 0 0 17 ffffffa7 c 0 0 0 0 0 1 0 20 0 1 0 0 0
ffffffd5 31 5d 5d 0 0 0 0 17 f
- 我使用的程式碼
#include"json.h"
int main(char* argc, char* argv[]){
FILE* fp = fopen("/dev/input/event8","r");
FILE* fp2 = fopen("log.txt","w");
char ch;
int n = 0;
char repr[10];
while(1){
ch = fgetc(fp);
if(n==24){
fputc('\n', fp2);
n = 0;
}
sprintf(repr, "%x", ch);
fputs(repr, fp2);
fputc(' ', fp2);
n++;
}
}
答案1
我無法找到一種方法來理解該條目的確切含義。
您的程式正在讀取的設備節點，
FILE* fp = fopen("/dev/input/event8","r");
是一種特殊類型的文件，稱為輸入事件介面。
從該文件讀取將傳回組織為的數據
struct input_event {
struct timeval time;
unsigned short type;
unsigned short code;
unsigned int value;
};
除了 key/eventcode和 key之外value，資料還包括時間戳記time。
The GNU C Library provides two data types specifically for representing an elapsed time.
They are used by various GNU C Library functions, and you can use them for your own purposes
too. They’re exactly the same except that one has a resolution in microseconds, and the other,
newer one, is in nanoseconds.
Data Type: struct timeval
The struct timeval structure represents an elapsed time. It is declared in sys/time.h
and has the following members:
time_t tv_sec
This represents the number of whole seconds of elapsed time.
long int tv_usec
This is the rest of the elapsed time (a fraction of a second), represented as
the number of microseconds. It is always less than one million.
描述了事件類型和事件代碼這裡。
嘗試使用該實用程式測試而不是您的程式來感受事件介面。
按下和釋放A按鍵的 EG 樣本輸出：
Event: time 1566419656.576267, -------------- SYN_REPORT ------------
Event: time 1566419662.463531, type 4 (EV_MSC), code 4 (MSC_SCAN), value 1e
Event: time 1566419662.463531, type 1 (EV_KEY), code 30 (KEY_A), value 1
Event: time 1566419662.463531, -------------- SYN_REPORT ------------
Event: time 1566419662.615625, type 4 (EV_MSC), code 4 (MSC_SCAN), value 1e
Event: time 1566419662.615625, type 1 (EV_KEY), code 30 (KEY_A), value 0
確保您了解原始鍵盤輸出，即掃描碼。
在 PC 上，鍵盤硬體會產生掃描代碼，以便可以偵測到每次按鍵（和釋放）。
由軟體來翻譯和重新映射按鍵，例如 ASCII 代碼或ANSI 轉義序列。