Timestamp interaction

This provides a level of interoperability with struct timeval on systems with that facility. More...

Namespaces
	osvr::util::time
	Functionality related to time and the OSVR_TimeValue abstraction.

Classes
struct	OSVR_TimeValue
	Standardized, portable parallel to struct timeval for representing both absolute times and time intervals. More...

Typedefs
typedef int64_t	OSVR_TimeValue_Seconds
	The signed integer type storing the seconds in a struct OSVR_TimeValue.
typedef int32_t	OSVR_TimeValue_Microseconds
	The signed integer type storing the microseconds in a struct OSVR_TimeValue.
typedef struct OSVR_TimeValue	OSVR_TimeValue
	Standardized, portable parallel to struct timeval for representing both absolute times and time intervals. More...

Functions
OSVR_UTIL_EXPORT void	osvrTimeValueNormalize (OSVR_INOUT_PTR OSVR_TimeValue *tv) OSVR_FUNC_NONNULL((1))
	"Normalizes" a time value so that the absolute number of microseconds is less than 1,000,000, and that the sign of both components is the same. More...
OSVR_UTIL_EXPORT void	osvrTimeValueSum (OSVR_INOUT_PTR OSVR_TimeValue *tvA, OSVR_IN_PTR const OSVR_TimeValue *tvB) OSVR_FUNC_NONNULL((1
	Sums two time values, replacing the first with the result. More...
OSVR_UTIL_EXPORT void OSVR_UTIL_EXPORT void	osvrTimeValueDifference (OSVR_INOUT_PTR OSVR_TimeValue *tvA, OSVR_IN_PTR const OSVR_TimeValue *tvB) OSVR_FUNC_NONNULL((1
	Computes the difference between two time values, replacing the first with the result. More...
OSVR_UTIL_EXPORT void OSVR_UTIL_EXPORT void OSVR_UTIL_EXPORT int	osvrTimeValueCmp (OSVR_IN_PTR const OSVR_TimeValue *tvA, OSVR_IN_PTR const OSVR_TimeValue *tvB) OSVR_FUNC_NONNULL((1
	Compares two time values (assumed to be normalized), returning the same values as strcmp. More...
OSVR_UTIL_EXPORT void OSVR_UTIL_EXPORT void OSVR_UTIL_EXPORT int OSVR_EXTERN_C_END OSVR_INLINE double	osvrTimeValueDurationSeconds (OSVR_IN_PTR const OSVR_TimeValue *tvA, OSVR_IN_PTR const OSVR_TimeValue *tvB)
	Compute the difference between the two time values, returning the duration as a double-precision floating-point number of seconds. More...
OSVR_INLINE OSVR_CBool	osvrTimeValueGreater (OSVR_IN_PTR const OSVR_TimeValue *tvA, OSVR_IN_PTR const OSVR_TimeValue *tvB)
	True if A is later than B.

Detailed Description

This provides a level of interoperability with struct timeval on systems with that facility.

It provides a neutral representation with sufficiently large types.

For C++ code, use of std::chrono or boost::chrono instead is recommended.

Note that these time values may not necessarily correlate between processes so should not be used to estimate or measure latency, etc.

Typedef Documentation

OSVR_TimeValue

typedef struct OSVR_TimeValue OSVR_TimeValue

Standardized, portable parallel to struct timeval for representing both absolute times and time intervals.

Where interpreted as an absolute time, its meaning is to be considered the same as that of the POSIX struct timeval: time since 00:00 Coordinated Universal Time (UTC), January 1, 1970.

For best results, please keep normalized. Output of all functions here is normalized.

Function Documentation

osvrTimeValueCmp()

OSVR_UTIL_EXPORT void OSVR_UTIL_EXPORT void OSVR_UTIL_EXPORT int osvrTimeValueCmp	(	OSVR_IN_PTR const OSVR_TimeValue *	tvA,
		OSVR_IN_PTR const OSVR_TimeValue *	tvB
	)

Compares two time values (assumed to be normalized), returning the same values as strcmp.

Returns

<0 if A is earlier than B, 0 if they are the same, and >0 if A is later than B.

osvrTimeValueDifference()

OSVR_UTIL_EXPORT void OSVR_UTIL_EXPORT void osvrTimeValueDifference	(	OSVR_INOUT_PTR OSVR_TimeValue *	tvA,
		OSVR_IN_PTR const OSVR_TimeValue *	tvB
	)

Computes the difference between two time values, replacing the first with the result.

Effectively, *tvA = *tvA - *tvB

Parameters

tvA	Destination and first source.
tvB	second source

If a given pointer is NULL, this function returns without doing anything.

Both parameters are expected to be in normalized form.

osvrTimeValueDurationSeconds()

OSVR_UTIL_EXPORT void OSVR_UTIL_EXPORT void OSVR_UTIL_EXPORT int OSVR_EXTERN_C_END OSVR_INLINE double osvrTimeValueDurationSeconds	(	OSVR_IN_PTR const OSVR_TimeValue *	tvA,
		OSVR_IN_PTR const OSVR_TimeValue *	tvB
	)

Compute the difference between the two time values, returning the duration as a double-precision floating-point number of seconds.

Effectively, ret = *tvA - *tvB

Parameters

tvA	first source.
tvB	second source

Returns

Duration of timespan in seconds (floating-point)

osvrTimeValueNormalize()

OSVR_UTIL_EXPORT void osvrTimeValueNormalize

(

OSVR_INOUT_PTR OSVR_TimeValue *

tv

)

"Normalizes" a time value so that the absolute number of microseconds is less than 1,000,000, and that the sign of both components is the same.

Parameters

tv	Address of a struct TimeValue to normalize in place.

If the given pointer is NULL, this function returns without doing anything.

osvrTimeValueSum()

OSVR_UTIL_EXPORT void osvrTimeValueSum	(	OSVR_INOUT_PTR OSVR_TimeValue *	tvA,
		OSVR_IN_PTR const OSVR_TimeValue *	tvB
	)

Sums two time values, replacing the first with the result.

Parameters

tvA	Destination and first source.
tvB	second source

If a given pointer is NULL, this function returns without doing anything.

Both parameters are expected to be in normalized form.