CTRL+D and CTRL+L signal handling

[mazazino]

hi..
im trynig to write a program that will catch when the user types in ctrl+d and i ctrl+L...so when im waiting to input and catch it using fgets() or some other function, i want to check if its ctrl+l or ctrl+d, how can i do that?..coz strcmp() can't check for such things..at least i dont think so..
and if these two keys generated a signal, then i should handle them using signal() function, but i dont know what signals they generated..i.e. ctrl+c generates a SIGINT..but i dont know what ctrl+d and ctrl+L generate..
any help would be appreciated..thanks..

[wje_lf]

If you're using fgets() or another standard I/O function to get your input, you won't see the ^L until the user enters some sort of end of line character.

Further, neither ^D nor ^L ordinarily generates a signal.

If you wish to have more fine-grained control, there are other functions you should use instead for your keyboard input. Do this at the command line:

man tcgetattr
man tcsetattr
man 2 read

If you do not have man pages installed on your system, google for this:

man tcgetattr linux
man tcsetattr linux
man read linux

Hope this helps.

[mazazino]

i know how to use the termios library, but the problem is that even if i use the termios functions, i still don't know what to check for..i mean ok so i use the termios to read a string, and then i want to check if this string is ctrl+l or ctrl+d, what are their hex values?

[wje_lf]

They're individual characters, not strings.

^A is 0x01.
^B is 0x02.

And so on through the English alphabet.

[mazazino]

ok ctrl+L turned up to be 0x0C, and i tried using scanf, any stdin function to get the char and check if its ctrl+L and it worked using its hex value, but ctrl+D sends some kind of signal to terminate the process im working in..
i.e. the execution of this program works fine:

#include <stdio.h>

int main()
{
	char c;
	printf("Write: ");
	scanf("%c", &c);
	if(c == 0x0C) printf("ctrl+L was entered\n");
	return 1;
}

but the execution of this doesnt..

#include <stdio.h>

int main()
{
	char c;
	printf("Write: ");
	scanf("%c", &c);
	if(c == 0x04) printf("ctrl+D was entered\n");
	return 1;
}

ctrl+d sends some kind of signal to terminate the process..but i thought it only sent a signal to kill a terminal process when its running...so how can ctrl+d be checked?..by signal()?..and if by signal(), whats the signal ctrl+d generates?..thanks..

[wje_lf]

how can ctrl+d be checked?

Don't use standard input. Use the functions I mentioned here.