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bsleep - Breakable sleep in C
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A couple of days ago I stumbled upon an improvised breakable sleep.
I wrote about in another post:
DIR 2024-06-25 - bsleep (bashism)
Since I generally strife to get independant from the use of bashisms, I
decided to rewrite bsleep in C.
And here we go...
Breakable sleep in C. The button 'b' breaks the sleep. This can be used
to chain two tasks on the commandline, with the second task only waiting
for you to press 'b'.
git clone git://kroovy.de/bsleep
Build dependencies
- C compiler
- libc
This program is meant to help people complete tasks on the commandline.
Also the source code can be studied as a simple approach to forking a
process in C.
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
int
main(void)
{
int i,in,pid;
pid = fork();
if (pid == 0) {
/* child */
for (i=1;;i++) {
printf("%d ", i); fflush(stdout); /* comment out if you prefer silent */
sleep(1);
}
return 0;
} else if (pid > 0) {
/* parent */
system ("/bin/stty raw");
while ((in = getchar()) != 'b') {
printf("%c ", in);
}
system ("/bin/stty cooked");
printf("\n");
kill(pid, SIGKILL); /* kill child */
return 0;
} else {
return -1;
}
return 0;
}
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Footnote:
The invocation of the operating system command "/bin/stty" via system()
is not the most elegant. At the moment this needed to read the character
without the need to press Enter.
If possible I will try to replace the call system("/bin/stty ...") in the
future.
DIR 2024-06-30 - bsleep (rewritten in C)