How to exit with Ctrl+D like bash with execl? - c

Question

I'm doing :
execl("/bin/bash", "/bin/bash", NULL);
When I do a Ctrl+D, it directly exit. How can I do the same as bash and write exit before exiting ?
Do I have to add a flag or something to execl?

Answer 1

When I compile execl(...), it prints exit on Ctrl-D just fine
#include <unistd.h>
int main(int argc, char **argv)
{
execl("/bin/bash", "/bin/bash", 0);
return 0;
}
maybe, you do a fork() or detach from the terminal or do something else, which lets bash assume it is non-interactive.
Ctrl-D is usually interpreted by the terminal. If you want to do this yourself, you must reset VEOF in the termios structure see c_cc for details.
This is a simplified example for handling Ctrl-D yourself. It still reads a whole line before processing anything, but you get the idea
#include <sys/wait.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <termios.h>
#include <unistd.h>
int main(int argc, char **argv)
{
char buf[100];
int fd;
struct termios tio;
fd = open("/dev/tty", O_RDWR);
if (fd < 0) {
perror("open tty");
exit(1);
}
memset(&tio, 0, sizeof(tio));
tcgetattr(fd, &tio);
tio.c_cc[VEOF] = 0;
tcflush(fd, TCIFLUSH);
tcsetattr(fd, TCSANOW, &tio);
while (fgets(buf, sizeof(buf), stdin)) {
if (buf[0] == 4) {
printf("Got Ctrl-D\n");
break;
}
}
return 0;
}
This program reads a line from the terminal, until it receives a line starting with Ctrl-D.
For more examples, see the Serial Programming HOWTO.