headers not working at a kernel level on eBPF code

So I'm developing something on eBPF.

I needed to use the unistd.h header because I wanted to use sleep function.

However, I realized that when I type in

#include <unistd.h>

these headers don't get included and I would get an error saying:

warning : implicit delcaration of function 'sleep' is invalid in C99 [-Wimplicit-Function-declaration] sleep (1);

I thought I have done something wrong somewhere else on the code so I tried to include that header on the example from the tutorial and it didn't work that way neither.

So from the code I have attached below, I tried to put a one second of delay before the message would be published.

Has anyone had a same issue and have somehow found a way to use that header inside the c code?

I would very much appreciate it if someone could land me some help!

Thanks a million!

I tried updating the kernel and moved all the header files to ёusr/local/includeё directory because it said on the internet that this is the place where the compiler first checks for headers but still didn't work.

So here's the code I tried but didn't work.

from bcc import BPF
BPF(text = 'int kprobe__sys_clone(void *ctx)
{
  #include <unistd.h>

  sleep(1);
  bpf_trace_printk("Hello World!\\n");
  return 0;
}
').trace_print()