Library: Foundation
Package: DateTime
Header: Poco/Timestamp.h
Description
A Timestamp stores a monotonic* time value with (theoretical) microseconds resolution. Timestamps can be compared with each other and simple arithmetic is supported.
[*] Note that Timestamp values are only monotonic as long as the systems's clock is monotonic as well (and not, e.g. set back due to time synchronization or other reasons).
Timestamps are UTC (Coordinated Universal Time) based and thus independent of the timezone in effect on the system.
The internal reference time is the Unix epoch, midnight, January 1, 1970.
Member Summary
Member Functions: elapsed, epochMicroseconds, epochTime, fromEpochTime, fromUtcTime, isElapsed, operator !=, operator +, operator +=, operator -, operator -=, operator <, operator <=, operator =, operator ==, operator >, operator >=, raw, resolution, swap, update, utcTime
Types Aliases
TimeDiff
Difference between two TimeVal values in microseconds.
TimeVal
Monotonic UTC time value in microsecond resolution, with base time midnight, January 1, 1970.
UtcTimeVal
using UtcTimeVal = Int64;
Monotonic UTC time value in 100 nanosecond resolution, with base time midnight, October 15, 1582.
Constructors
Timestamp
Timestamp();
Creates a timestamp with the current time.
Timestamp
Creates a timestamp from the given time value (microseconds since midnight, January 1, 1970).
Timestamp
Timestamp(
const Timestamp & other
);
Copy constructor.
Destructor
~Timestamp
~Timestamp();
Destroys the timestamp
Member Functions
elapsed 
TimeDiff elapsed() const;
Returns the time elapsed since the time denoted by the timestamp. Equivalent to Timestamp() - *this.
epochMicroseconds
TimeVal epochMicroseconds() const;
Returns the timestamp expressed in microseconds since the Unix epoch, midnight, January 1, 1970.
epochTime
std::time_t epochTime() const;
Returns the timestamp expressed in time_t. time_t base time is midnight, January 1, 1970. Resolution is one second.
fromEpochTime 
static Timestamp fromEpochTime(
std::time_t t
);
Creates a timestamp from a std::time_t.
fromUtcTime
static Timestamp fromUtcTime(
UtcTimeVal val
);
Creates a timestamp from a UTC time value (100 nanosecond intervals since midnight, October 15, 1582).
isElapsed
bool isElapsed(
TimeDiff interval
) const;
Returns true iff the given interval has passed since the time denoted by the timestamp.
operator !=
bool operator != (
const Timestamp & ts
) const;
operator +
Timestamp operator + (
TimeDiff d
) const;
operator +
Timestamp operator + (
const Timespan & span
) const;
operator +=
Timestamp & operator += (
TimeDiff d
);
operator +=
Timestamp & operator += (
const Timespan & span
);
operator -
Timestamp operator - (
TimeDiff d
) const;
operator -
Timestamp operator - (
const Timespan & span
) const;
operator -
TimeDiff operator - (
const Timestamp & ts
) const;
operator -=
Timestamp & operator -= (
TimeDiff d
);
operator -=
Timestamp & operator -= (
const Timespan & span
);
operator <
bool operator < (
const Timestamp & ts
) const;
operator <=
bool operator <= (
const Timestamp & ts
) const;
operator =
Timestamp & operator = (
const Timestamp & other
);
operator =
Timestamp & operator = (
TimeVal tv
);
operator ==
bool operator == (
const Timestamp & ts
) const;
operator >
bool operator > (
const Timestamp & ts
) const;
operator >=
bool operator >= (
const Timestamp & ts
) const;
raw
TimeVal raw() const;
Returns the raw time value.
Same as epochMicroseconds().
resolution
static constexpr TimeDiff resolution();
Returns the resolution in units per second. Since the timestamp has microsecond resolution, the returned value is always 1000000.
swap
void swap(
Timestamp & timestamp
) noexcept;
Swaps the Timestamp with another one.
update
void update();
Updates the Timestamp with the current time.
utcTime
UtcTimeVal utcTime() const;
Returns the timestamp expressed in UTC-based time. UTC base time is midnight, October 15, 1582. Resolution is 100 nanoseconds.
Variables
TIMEVAL_MAX
static const TimeVal TIMEVAL_MAX;
Maximum timestamp value.
TIMEVAL_MIN
static const TimeVal TIMEVAL_MIN;
Minimum timestamp value.