rt-thread/components/libc/time/posix_sleep.c

#include <stdlib.h>
#include <rtthread.h>

#include <unistd.h>

unsigned int sleep(unsigned int seconds)
{
    rt_tick_t delta_tick;

    delta_tick = rt_tick_get();
    rt_thread_delay(seconds * RT_TICK_PER_SECOND);
    delta_tick = rt_tick_get() - delta_tick;

    return seconds - delta_tick/RT_TICK_PER_SECOND;
}