1 /* -----------------------------------------------------------------------------
2 * $Id: Itimer.c,v 1.2 1998/12/02 13:28:27 simonm Exp $
4 * (c) The GHC Team, 1995-1998
6 * Interval timer for profiling and pre-emptive scheduling.
8 * ---------------------------------------------------------------------------*/
11 * The interval timer is used for profiling and for context switching in the
12 * threaded build. Though POSIX 1003.1b includes a standard interface for
13 * such things, no one really seems to be implementing them yet. Even
14 * Solaris 2.3 only seems to provide support for @CLOCK_REAL@, whereas we're
15 * keen on getting access to @CLOCK_VIRTUAL@.
17 * Hence, we use the old-fashioned @setitimer@ that just about everyone seems
18 * to support. So much for standards.
22 # define NON_POSIX_SOURCE
28 /* As recommended in the autoconf manual */
29 # ifdef TIME_WITH_SYS_TIME
30 # include <sys/time.h>
33 # ifdef HAVE_SYS_TIME_H
34 # include <sys/time.h>
41 * Handling timer events under cygwin32 is not done with signal/setitimer.
42 * Instead of the two steps of first registering a signal handler to handle
43 * \tr{SIGVTALRM} and then start generating them via @setitimer()@, we use
44 * the Multimedia API (MM) and its @timeSetEvent@. (Internally, the MM API
45 * creates a separate thread that will notify the main thread of timer
46 * expiry). -- SOF 7/96
48 * 11/98: if the cygwin DLL supports setitimer(), then use it instead.
51 #if defined(cygwin32_TARGET_OS) && !defined(HAVE_SETITIMER)
53 #include <windows.h> /* OK, bring it all in... */
56 vtalrm_handler is assigned and set up in
59 vtalrm_id (defined in main/Signals.lc) holds
60 the system id for the current timer (used to
61 later block/kill the timer)
64 extern TIMECALLBACK *vtalrm_cback;
67 initialize_virtual_timer(nat ms)
69 /* VTALRM is currently not supported by cygwin32,
70 so we use the Timer support provided by the
71 MultiMedia API that is part of Win32. The
72 parameters to timeSetEvent may require some tweaking.
74 unsigned int delay,vtalrm_id;
76 delay = timeBeginPeriod(1);
77 if (delay == TIMERR_NOCANDO) { /* error of some sort. */
81 timeSetEvent(ms, /* event every `delay' milliseconds. */
82 1, /* precision is within 5 millisecs. */
83 (LPTIMECALLBACK)vtalrm_cback,
92 initialize_virtual_timer(nat ms)
94 # ifndef HAVE_SETITIMER
95 fprintf(stderr, "No virtual timer on this system\n");
100 it.it_value.tv_sec = ms / 1000;
101 it.it_value.tv_usec = 1000 * (ms - (1000 * it.it_value.tv_sec));
102 it.it_interval = it.it_value;
103 return (setitimer(ITIMER_VIRTUAL, &it, NULL));
107 #endif /* !cygwin32_TARGET_OS */
110 /* This is a potential POSIX version */
112 initialize_virtual_timer(nat ms)
115 struct itimerspec it;
118 se.sigev_notify = SIGEV_SIGNAL;
119 se.sigev_signo = SIGVTALRM;
120 se.sigev_value.sival_int = SIGVTALRM;
121 if (timer_create(CLOCK_VIRTUAL, &se, &tid)) {
122 fprintf(stderr, "Can't create virtual timer.\n");
125 it.it_value.tv_sec = ms / 1000;
126 it.it_value.tv_nsec = 1000000 * (ms - 1000 * it.it_value.tv_sec);
127 it.it_interval = it.it_value;
128 timer_settime(tid, TIMER_RELTIME, &it, NULL);
133 install_vtalrm_handler(void (*handler)(int))
135 struct sigaction action;
137 action.sa_handler = handler;
139 sigemptyset(&action.sa_mask);
142 return sigaction(SIGVTALRM, &action, NULL);
146 block_vtalrm_signal(void)
150 sigemptyset(&signals);
151 sigaddset(&signals, SIGVTALRM);
153 (void) sigprocmask(SIG_BLOCK, &signals, NULL);
157 unblock_vtalrm_signal(void)
161 sigemptyset(&signals);
162 sigaddset(&signals, SIGVTALRM);
164 (void) sigprocmask(SIG_UNBLOCK, &signals, NULL);