zclock(3)

zclock(3)

CZMQ Manual - CZMQ/3.0.1

Name

zclock - millisecond clocks and delays

Synopsis

//  Sleep for a number of milliseconds
CZMQ_EXPORT void
    zclock_sleep (int msecs);

//  Return current system clock as milliseconds. Note that this clock can
//  jump backwards (if the system clock is changed) so is unsafe to use for
//  timers and time offsets. Use zclock_mono for that instead.
CZMQ_EXPORT int64_t
    zclock_time (void);

//  Return current monotonic clock in milliseconds. Use this when you compute
//  time offsets. The monotonic clock is not affected by system changes and
//  so will never be reset backwards, unlike a system clock.
CZMQ_EXPORT int64_t
    zclock_mono (void);

//  Return current monotonic clock in microseconds. Use this when you compute
//  time offsets. The monotonic clock is not affected by system changes and
//  so will never be reset backwards, unlike a system clock.
CZMQ_EXPORT int64_t
    zclock_usecs (void);

//  Return formatted date/time as fresh string. Free using zstr_free().
CZMQ_EXPORT char *
    zclock_timestr (void);

//  Self test of this class
CZMQ_EXPORT void
    zclock_test (bool verbose);

Description

The zclock class provides essential sleep and system time functions, used to slow down threads for testing, and calculate timers for polling. Wraps the non-portable system calls in a simple portable API.

The Win32 Sleep() call defaults to 16ms resolution unless the system timer resolution is increased with a call to timeBeginPeriod() permitting 1ms granularity.

Example

From zclock_test method

int64_t start = zclock_time ();
zclock_sleep (10);
assert ((zclock_time () - start) >= 10);
start = zclock_mono ();
int64_t usecs = zclock_usecs ();
zclock_sleep (10);
assert ((zclock_mono () - start) >= 10);
assert ((zclock_usecs () - usecs) >= 10000);
char *timestr = zclock_timestr ();
if (verbose)
 puts (timestr); free (timestr);

See also

czmq(7)

Authors

The CZMQ manual was written by Pieter Hintjens<moc.xitami|hp#moc.xitami|hp>.

Resources

Main web site: http://czmq.zeromq.org/

Report bugs to the ØMQ development mailing list: <gro.qmorez.stsil|ved-qmorez#gro.qmorez.stsil|ved-qmorez>

Copyright

Copyright (c) the Contributors as noted in the AUTHORS file. This file is part of CZMQ, the high-level C binding for ØMQ: http://czmq.zeromq.org. This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0. If a copy of the MPL was not distributed with this file, You can obtain one at http://mozilla.org/MPL/2.0/.