Functions for accessing a monotonic wall clock. More...

Functions
static double	get_wclock (const wclock *clock)
	Retrieve the time from a monotonic wall clock in seconds. More...

static double	get_wclock_res (const wclock *clock)
	Obtain the resolution of the monotonic wall clock in seconds. More...

static int	init_wclock (wclock *clock)
	Initialize a value needed to access the monotonic wall clock. More...

Detailed Description

Functions for accessing a monotonic wall clock.

Note: on systems other than Windows or Mac OS X, it is strongly recommended to define _POSIX_C_SOURCE to a value of at least 199309L before the inclusion of this header or any system header.

Function Documentation

double get_wclock ( const wclock * clock )

inlinestatic

Retrieve the time from a monotonic wall clock in seconds.

Parameters

clock An wclock value previously initialized by init_wclock.

Returns: Duration relative to some unspecified reference time in seconds. If an error occurs, NAN is returned.

Due to the use of double-precision floating point numbers, the precision is at worst (for an ideal system with hundreds of years in uptime) limited to about a few microseconds. In practice, it is usually much less.

double get_wclock_res ( const wclock * clock )

inlinestatic

Obtain the resolution of the monotonic wall clock in seconds.

Parameters

clock An wclock value previously initialized by init_wclock.

Returns: Duration relative to some unspecified reference time in seconds. If an error occurs, NAN is returned.

int init_wclock ( wclock * clock )

inlinestatic

Initialize a value needed to access the monotonic wall clock.

The clock does not need to be deinitialized.

Parameters

clock An existing wclock value to be initialized.

Returns: Zero on success, nonzero on failure.