1 /* 2 * now.h - some simple minded time measurement support for nana. 3 * 4 * Copyright (c) 1997 Phil Maker 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 * 28 * Id: now.h,v 1.2 1998/07/08 10:56:12 pjm Exp 29 */ 30 31 32 #ifndef _now_h_ 33 #define _now_h_ 1 34 35 #ifdef __cplusplus 36 extern "C" { 37 #endif 38 39 /* 40 * now() - returns the current real time in seconds from the wallclock 41 * using gettimeofday(2). Accuracy (quoted from IPM documentation) is: 42 * 43 * SUNOS 4 and 5, HPUX approx 1us 44 * Linux approx 100us 45 * SGI, AIX approx 10ms 46 * 47 * If you need something a bit faster try either the cycles.h library 48 * or use $cycles in the simulator. 49 */ 50 51 double now(void); 52 53 /* 54 * now_reset() - resets the values returned by now() back to 0 so that 55 * the values are a little smaller. You might use this as part of your 56 * initialisation sequence to make time values easier to read (e.g. 57 * 123.4566 rather than 81828282.8888) 58 */ 59 60 void now_reset(void); 61 62 /* 63 * now_delta(t) - used to make a delta time counter, the argument is the 64 * used to record the last event we are measuring the time from. 65 * 66 * t = now(); ...; now_delta(&t); ...; now_delta(&t); ... 67 * 68 */ 69 70 double now_delta(double *t); 71 72 #ifdef __cplusplus 73 } 74 #endif 75 76 #endif /* _now_h_ */ 77 78