C - CTRL +字符的输入测试

Question

是想知道如何如何测试在Char数组中保存的输入，如...

   char input[INPUT_SIZE];

.

和使用

fgets(input,INPUT_SIZE,stdin);

. 要从用户获取输入，但想知道如何使用IF语句来测试用户输入是否已进行测试 ctrl + d 或任何 ctrl +任何keke？

我用那里使用这样的ascci值..是测试Ctrl D 的示例

  if(result = 'EOT') {printf("EOT");}

.

结果是Anwell。

Answer 1

You can only test Ctrl+d as your read returning EOF, see the manual of your read to have more info on this, but generally it returns 0. Same goes for Ctrl+c, as both are sending signals to your program.

For other Ctrl+key combinations, it highly depends on your system.

On linux Ctrl+a and Ctrl+e in a shell or emacs will move you to the beginning or the end / beginning of the line respectively.

The easiest to get what you want is to write a small program using read, unbuffered (see ioctl), with a 8-bytes buffer, and dump your read bytes each time you exit the read.

int nbr;
int i;
char buf[8];

nbr = 42;
while (nbr > 0)
{
  nbr = read(0, buf, 8);
  i = 0;
  while (i < nbr)
    printf("%x ", buf[i++]);
  printf("\n");
}

You will have the hex version of the ctrl+key received sequences. Likely to begin with \ESC or \033 (the escape character sequence). For example the arrow-up key looks like \033[A