cosmos::Clock< CLOCK > Class Template Reference

C++ wrapper around the POSIX clocks and related functions. More...

#include <Clock.hxx>

Public Member Functions
void	now (TimeSpec< CLOCK > &ts) const
	Retrieve the current value of the clock.
TimeSpec< CLOCK >	now () const
	Returns the current value of the clock by value.
TimeSpec< CLOCK >	resolution () const
	Returns the resolution/precision of the represented clock.
void	setTime (const TimeSpec< CLOCK > t)
	Changes the current time value of the represented clock.
void	sleep (const TimeSpec< CLOCK > until) const
	Suspend execution of the calling thread until the clock reaches the given time.

Static Public Member Functions
static ClockType	raw ()

Detailed Description

template<ClockType CLOCK>
class cosmos::Clock< CLOCK >

C++ wrapper around the POSIX clocks and related functions.

This is a template to make different clock types incompatible with each other.

Definition at line 16 of file Clock.hxx.

Member Function Documentation

now() [1/2]

template<ClockType CLOCK>

TimeSpec< CLOCK > cosmos::Clock< CLOCK >::now ( ) const

inline

Returns the current value of the clock by value.

Definition at line 23 of file Clock.hxx.

                                    {
                TimeSpec<CLOCK> ret;
                now(ret);
                return ret;
        }

now() [2/2]

template<ClockType CLOCK>

void cosmos::Clock< CLOCK >::now

(

TimeSpec< CLOCK > &

ts

)

const

Retrieve the current value of the clock.

Definition at line 23 of file Clock.cxx.

                                                {
        auto res = clock_gettime(to_integral(CLOCK), &ts);
 
        if (res != 0) {
                cosmos_throw (ApiError("clock_gettime()"));
        }
}

raw()

template<ClockType CLOCK>

static ClockType cosmos::Clock< CLOCK >::raw ( )

inlinestatic

Definition at line 60 of file Clock.hxx.

{ return CLOCK; }

resolution()

template<ClockType CLOCK>

TimeSpec< CLOCK > cosmos::Clock< CLOCK >::resolution

(

)

const

Returns the resolution/precision of the represented clock.

The returned TimeSpec represents the smallest time unit that can be processed / detected by the clock. When calling setTime() then the used time value is truncated to a multiple of the resolution value returned from this function.

Definition at line 32 of file Clock.cxx.

                                               {
        TimeSpec<CLOCK> ret;
        auto res = clock_getres(to_integral(CLOCK), &ret);
 
        if (res != 0) {
                cosmos_throw (ApiError("clock_getres()"));
        }
 
        return ret;
}

setTime()

template<ClockType CLOCK>

void cosmos::Clock< CLOCK >::setTime

(

const TimeSpec< CLOCK >

t

)

Changes the current time value of the represented clock.

Elevated permissions are necessary to change most clocks e.g. CAP_SYS_TIME to change the RealTimeClock. Not all clocks can be set. If this is the case then an ApiError with Errno::INVALID_ARG is thrown.

Definition at line 44 of file Clock.cxx.

                                                  {
        auto res = clock_settime(to_integral(CLOCK), &t);
 
        if (res != 0) {
                cosmos_throw (ApiError("clock_settime()"));
        }
}

sleep()

template<ClockType CLOCK>

void cosmos::Clock< CLOCK >::sleep

(

const TimeSpec< CLOCK >

until

)

const

Suspend execution of the calling thread until the clock reaches the given time.

The given until value is an absolute time in the future until which the execution of the calling thread is to be suspended. If until is not in the future then this call returns immediately without entering a suspend state.

Depending of the libcosmos "automatic restart on interrupt" setting, this call can be interrupted by signals which will cause an ApiError with Errno::INTERRUPTED to be thrown.

Definition at line 53 of file Clock.cxx.

                                                          {
        while (true) {
                auto res = clock_nanosleep(
                                to_integral(CLOCK),
                                TIMER_ABSTIME,
                                &until,
                                nullptr
                );
 
                const auto err = Errno{res};
 
                switch(err) {
                        default: break;
                        case Errno::NO_ERROR: return;
                        case Errno::INTERRUPTED: {
                                if (auto_restart_syscalls) {
                                        continue;
                                }
                                break;
                        }
                }
 
                cosmos_throw (ApiError("clock_nanosleep()", err));
        }
}

---

The documentation for this class was generated from the following files:

• include/time/Clock.hxx
• src/time/Clock.cxx