in Sat, Jul 12, 2008 at 12:24 PM, pei lin <telent998@xxxxxxxxx> wrote:
> Hi,buddy
> I am puzzled by the linux termios.
> First Question about /dev/tty0 and /dev/tty,this two devices is
> the same one?
> When i am in X terminal,as /dev/pts/0 , i do "echo hello >
> /dev/pts/0 and echo hello > /dev/tty ", they return the same like that
> "hello" on the screen .This means /dev/tty ->/dev/pts/0? But "echo
> hello > /dev/tty0",there is nothing on the screen.And when i go to
> Init 3 mode ,like /dev/tty1,when i do "echo hello > /dev/tty1 and echo
> hello > .dev/tty and echo hello > /dev/tty0" ,They return the same all
> print hello on the screen.Do they all point to the /dev/tty1?
/dev/tty is a pointer to the current tty. whether it be /dev/tty1 or
/dev/pts/0. when you login you are assigned a tty and if you
don't know it you can just use /dev/tty and it will open the current
tty
> The second Question is that i write a small program to get
> keyboard input like below.When i run it in X terminal ,when i press
> keyboard it can return but can not get the press and release event.And
> in the console,like tty1,it doesn't work .i don't know why.
>
> file : get_keyboard.c
>
> #include <stdio.h>
> #include <linux/keyboard.h>
> #include <sys/ioctl.h>
> #include <fcntl.h>
> #include <linux/kd.h>
> #include <termios.h>
> #include <unistd.h>
> int main()
> {
> int fd,len,i;
> struct kbentry entry;
> unsigned char buf[64];
> struct termios ts,old_ts;
> char * path;
> path = ttyname(0);
> printf("%s!\n",path);
> fd = open(path, O_RDONLY|O_NOCTTY);
> if(fd < 0){
> printf("open the device error!\n");
> }
>
> printf("fd --- %d!\n",fd);
>
> if (ioctl( fd, KDSKBMODE, K_RAW ) < 0) {
> printf("set mode wrong!\n");
> }
>
>
> tcgetattr( fd, &old_ts );
>
>
> ts = old_ts;
> ts.c_cc[VTIME] = 0;
> ts.c_cc[VMIN] = 1;
> ts.c_lflag &= ~(ICANON|ECHO|ISIG);
> ts.c_iflag = 0;
> tcsetattr( fd, TCSAFLUSH, &ts );
>
> tcsetpgrp( fd, getpgrp() );
>
>
> entry.kb_table = K_NORMTAB;
> entry.kb_value = 0;
>
> while(1){
> len=read(fd,buf,64);
> printf("len ========= %d!\n",len);
> for(i =0; i < len;i++){
> entry.kb_index = buf[i];
> if(ioctl(fd,KDGKBENT,&entry)){
> printf("struct entry :%d %d
> %d\n",entry.kb_table,entry.kb_index,entry.kb_value);
> if('2' == entry.kb_index){
> tcsetattr( fd, TCSAFLUSH, &old_ts );
> exit(0);
> }
> }
> }
> }
> }
> --
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