Smeed: C time macros - second based.

gistfile1.c

#include <time.h>

/* The following timing-related macros are based on the reaction.c
 * versions except that they are time_t and time() specific rather
 * than clock_t and clock() specific since the latter aren't
 * suitable for timing I/O bound programs.
 */
static time_t _startTime,_stopTime;   /* 'private' variables */
#define SNAP() (_startTime = time(NULL))
#define SHOT() (_stopTime  = time(NULL))
#define ELAPSED() (difftime(_stopTime,_startTime))
#define RUNTIME() (difftime(time(NULL),_startTime))
/* PAUSE(): a crude delay system - it waits for d seconds to expire. */
#define PAUSE(d) {SNAP();while ((int)RUNTIME() < d);}