// fg_timer.cxx -- time handling routines // // Written by Curtis Olson, started June 1997. // // Copyright (C) 1997 Curtis L. Olson - http://www.flightgear.org/~curt // // This program is free software; you can redistribute it and/or // modify it under the terms of the GNU General Public License as // published by the Free Software Foundation; either version 2 of the // License, or (at your option) any later version. // // This program is distributed in the hope that it will be useful, but // WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU // General Public License for more details. // // You should have received a copy of the GNU General Public License // along with this program; if not, write to the Free Software // Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. // // $Id$ #ifdef HAVE_CONFIG_H # include #endif #include // for timer routines #include // for printf() #ifdef HAVE_STDLIB_H # include #endif #ifdef HAVE_SYS_TIME_H # include // for get/setitimer, gettimeofday, struct timeval #endif #include #include "fg_timer.hxx" unsigned long int fgSimTime; #ifdef HAVE_SETITIMER static struct itimerval t, ot; static void (*callbackfunc)(int multi_loop); // This routine catches the SIGALRM void fgTimerCatch( int dummy ) { int warning_avoider; // get past a compiler warning warning_avoider = dummy; // ignore any SIGALRM's until we come back from our EOM iteration signal(SIGALRM, SIG_IGN); // printf("In fgTimerCatch()\n"); // -1 tells the routine to use default interval rather than // something dynamically calculated based on frame rate callbackfunc(-1); signal(SIGALRM, fgTimerCatch); } // this routine initializes the interval timer to generate a SIGALRM // after the specified interval (dt) void fgTimerInit(float dt, void (*f)( int )) { int terr; int isec; int usec; callbackfunc = f; isec = (int) dt; usec = 1000000 * ((int)dt - isec); t.it_interval.tv_sec = isec; t.it_interval.tv_usec = usec; t.it_value.tv_sec = isec; t.it_value.tv_usec = usec; // printf("fgTimerInit() called\n"); fgTimerCatch(0); // set up for SIGALRM signal catch terr = setitimer( ITIMER_REAL, &t, &ot ); if (terr) { printf("Error returned from setitimer"); exit(0); } } #endif // HAVE_SETITIMER // This function returns the number of microseconds since the last // time it was called. int fgGetTimeInterval( void ) { int interval; static int inited = 0; static SGTimeStamp last; SGTimeStamp current; if ( ! inited ) { inited = 1; last.stamp(); interval = 0; } else { current.stamp(); interval = current - last; last = current; } return interval; }