Crossplatform software delays

This is the simple macros for different delays usuable on Unix and Windows:

#ifndef _DELAYS_H
#define _DELAYS_H

#include 
#include 

/* Converting between seconds and CPU ticks (clock_t):
 *      MS2TICKS() converts milliseconds to ticks
 *      US2TICKS() converts microseconds to ticks
 *      TICKS2MS() converts ticks to milliseconds
 *      TICKS2US() converts ticks to microseconds
 */
#define MS2TICKS(MS) ((MS)*(CLOCKS_PER_SEC)/1000)
#define US2TICKS(US) ((US)*(CLOCKS_PER_SEC)/1000000)
#define TICKS2MS(T)  ((T)/((CLOCKS_PER_SEC)*1000))
#define TICKS2US(T)  ((T)/((CLOCKS_PER_SEC)*1000000))

/*
 * delay(MS)         sleeping on MS milliseconds
 */
#if defined(WIN32) || defined(_WIN32) || defined(__WIN32)
#  include 
#  define delay(MS) Sleep(MS)
#else
#  if defined(HAVE_USLEEP)
#    define delay(MS) usleep((MS)*1000)
#  elif defined(HAVE_SLEEP)
#    include 
#    define delay(MS) sleep((MS)/1000) /* granularity only ONE SECOND! */
#  else
#    error Can not found any sleep_clocks() implementation ideas
# endif
#endif

/*
 * pthread_delay(MS) sleeping thread on MS milliseconds
 */
#if defined(HAVE_PTHREAD_DELAY_NP)
#  define pthread_delay(MS) \
     do { \
             struct timespec __timespec={(MS)/1000,((MS)%1000)*1000000000}; \
             pthread_delay_np(&__timespec); \
     } \
     while(0)
#else
#  define pthread_delay(MS) delay(MS)
#endif

/*
 * unow(PNOW) store in var pointed by PNOW microseconds since Epoch
 */
#define unow(PNOW) \
{ \
        struct timeval __tv;  \
        gettimeofday(&__tv, NULL); \
        *(PNOW) = (__tv.tv_sec * 1000000) + __tv.tv_usec; \
}

#endif /*!_DELAYS_H*/

If HAVE_PTHREAD_DELAY_NP will be defined before including of this file, then pthread_delay() will be wrapper for pthread_delay_np() - see Pthreads for Win32 headers.