microtime(3) [php man page]

MICROTIME(3)								 1							      MICROTIME(3)

microtime - Return current Unix timestamp with microseconds

SYNOPSIS

       mixed microtime ([bool  $get_as_float = false])

DESCRIPTION

       microtime(3)  returns  the  current Unix timestamp with microseconds. This function is only available on operating systems that support the
       gettimeofday() system call.

PARAMETERS

	      o $get_as_float
		- If used and set to TRUE, microtime(3) will return a float instead of a string, as described in the return values section below.

RETURN VALUES

	By default, microtime(3) returns a string in the form "msec sec", where sec is the number of seconds since the Unix epoch (0:00:00 January
       1,1970 GMT), and msec measures microseconds that have elapsed since sec and is also expressed in seconds.

	If  $get_as_float  is  set  to	TRUE, then microtime(3) returns a float, which represents the current time in seconds since the Unix epoch
       accurate to the nearest microsecond.

EXAMPLES

       Example #1

	      Timing script execution with microtime(3)

	      <?php
	      /**
	       * Simple function to replicate PHP 5 behaviour
	       */
	      function microtime_float()
	      {
		  list($usec, $sec) = explode(" ", microtime());
		  return ((float)$usec + (float)$sec);
	      }

	      $time_start = microtime_float();

	      // Sleep for a while
	      usleep(100);

	      $time_end = microtime_float();
	      $time = $time_end - $time_start;

	      echo "Did nothing in $time seconds
";
	      ?>

       Example #2

	      Timing script execution in PHP 5

	      <?php
	      $time_start = microtime(true);

	      // Sleep for a while
	      usleep(100);

	      $time_end = microtime(true);
	      $time = $time_end - $time_start;

	      echo "Did nothing in $time seconds
";
	      ?>

       Example #3

	      microtime(3) and REQUEST_TIME_FLOAT (as of PHP 5.4.0)

	      <?php
	      // Randomize sleeping time
	      usleep(mt_rand(100, 10000));

	      // As of PHP 5.4.0, REQUEST_TIME_FLOAT is available in the $_SERVER superglobal array.
	      // It contains the timestamp of the start of the request with microsecond precision.
	      $time = microtime(true) - $_SERVER["REQUEST_TIME_FLOAT"];

	      echo "Did nothing in $time seconds
";
	      ?>

SEE ALSO

       time(3).

PHP Documentation Group 													      MICROTIME(3)

MICROTIME(9)						   BSD Kernel Developer's Manual					      MICROTIME(9)

NAME

     bintime, getbintime, microtime, getmicrotime, nanotime, getnanotime -- get the current time

SYNOPSIS

     #include <sys/time.h>

     void
     bintime(struct bintime *bt);

     void
     getbintime(struct bintime *bt);

     void
     microtime(struct timeval *tv);

     void
     getmicrotime(struct timeval *tv);

     void
     nanotime(struct timespec *ts);

     void
     getnanotime(struct timespec *tsp);

DESCRIPTION

     The bintime() and getbintime() functions store the system time as a struct bintime at the addresses specified by bt.  The microtime() and
     getmicrotime() functions perform the same utility, but record the time as a struct timeval instead.  Similarly the nanotime() and
     getnanotime() functions store the time as a struct timespec.  The structures are described in timeval(3).

     The bintime(), microtime(), and nanotime() functions always query the timecounter to return the current time as precisely as possible.
     Whereas getbintime(), getmicrotime(), and getnanotime() functions are abstractions which return a less precise, but faster to obtain, time.

     The intent of the getbintime(), getmicrotime(), and getnanotime() functions is to enforce the user's preference for timer accuracy versus
     execution time.  They should be used where a precision of 1/HZ (e.g., 10 msec on a 100HZ machine, see hz(9)) is acceptable or where perfor-
     mance is priority.

     The system realtime clock is guaranteed to be monotonically increasing at all times.  As such, all calls to these functions are guaranteed to
     return a system time greater than or equal to the system time returned in any previous calls.  Comparable functions exist to retrieve the
     time elapsed since boot; see microuptime(9).

SEE ALSO

     settimeofday(2), bintime_add(9), inittodr(9), time_second(9), tvtohz(9)

CODE REFERENCES

     The implementation of the microtime() family of functions is in sys/kern/kern_tc.c as a part of the timecounter(9) framework.

     The implementation of the time counter sources used by the timecounter(9) is machine dependent, hence its location in the source code tree
     varies from architecture to architecture.

AUTHORS

     This manual page was written by Jeremy Cooper and
     Kelly Yancey <kbyanc@posi.net>.

BUGS

     Despite the guarantee that the system realtime clock will always be monotonically increasing, it is always possible for the system clock to
     be manually reset by the system administrator to any date.

BSD
								   June 8, 2010 							       BSD