all repos — slstatus @ 914440b4fc3c5ecb7d9eedf4da6f2a1c7ec2e7a9

my build of slstatus (tools.suckless.org/slstatus/)

entropy.c

1 2 3 4 5 6 7 8 9 10 11 12
#include <stdio.h>

#include "util.h"

const char *
entropy(void)
{
	int num;

	return (pscanf("/proc/sys/kernel/random/entropy_avail", "%d", &num) == 1) ?
	               bprintf("%d", num) : NULL;
}