rcutils  master
C API providing common utilities and data structures.
Macros | Typedefs | Functions
time.h File Reference
#include <stdint.h>
#include "rcutils/macros.h"
#include "rcutils/types.h"
#include "rcutils/visibility_control.h"

Go to the source code of this file.

Macros

#define RCUTILS_S_TO_NS(seconds)   (seconds * (1000 * 1000 * 1000))
 Convenience macro to convert seconds to nanoseconds. More...
 
#define RCUTILS_MS_TO_NS(milliseconds)   (milliseconds * (1000 * 1000))
 Convenience macro to convert milliseconds to nanoseconds. More...
 
#define RCUTILS_US_TO_NS(microseconds)   (microseconds * 1000)
 Convenience macro to convert microseconds to nanoseconds. More...
 
#define RCUTILS_NS_TO_S(nanoseconds)   (nanoseconds / (1000 * 1000 * 1000))
 Convenience macro to convert nanoseconds to seconds. More...
 
#define RCUTILS_NS_TO_MS(nanoseconds)   (nanoseconds / (1000 * 1000))
 Convenience macro to convert nanoseconds to milliseconds. More...
 
#define RCUTILS_NS_TO_US(nanoseconds)   (nanoseconds / 1000)
 Convenience macro to convert nanoseconds to microseconds. More...
 

Typedefs

typedef uint64_t rcutils_time_point_value_t
 A single point in time, measured in nanoseconds since the Unix epoch. More...
 
typedef int64_t rcutils_duration_value_t
 A duration of time, measured in nanoseconds. More...
 

Functions

rcutils_ret_t rcutils_system_time_now (rcutils_time_point_value_t *now)
 
rcutils_ret_t rcutils_steady_time_now (rcutils_time_point_value_t *now)
 Retrieve the current time as a rcutils_time_point_value_t object. More...
 

Macro Definition Documentation

◆ RCUTILS_S_TO_NS

#define RCUTILS_S_TO_NS (   seconds)    (seconds * (1000 * 1000 * 1000))

Convenience macro to convert seconds to nanoseconds.

◆ RCUTILS_MS_TO_NS

#define RCUTILS_MS_TO_NS (   milliseconds)    (milliseconds * (1000 * 1000))

Convenience macro to convert milliseconds to nanoseconds.

◆ RCUTILS_US_TO_NS

#define RCUTILS_US_TO_NS (   microseconds)    (microseconds * 1000)

Convenience macro to convert microseconds to nanoseconds.

◆ RCUTILS_NS_TO_S

#define RCUTILS_NS_TO_S (   nanoseconds)    (nanoseconds / (1000 * 1000 * 1000))

Convenience macro to convert nanoseconds to seconds.

◆ RCUTILS_NS_TO_MS

#define RCUTILS_NS_TO_MS (   nanoseconds)    (nanoseconds / (1000 * 1000))

Convenience macro to convert nanoseconds to milliseconds.

◆ RCUTILS_NS_TO_US

#define RCUTILS_NS_TO_US (   nanoseconds)    (nanoseconds / 1000)

Convenience macro to convert nanoseconds to microseconds.

Typedef Documentation

◆ rcutils_time_point_value_t

typedef uint64_t rcutils_time_point_value_t

A single point in time, measured in nanoseconds since the Unix epoch.

◆ rcutils_duration_value_t

typedef int64_t rcutils_duration_value_t

A duration of time, measured in nanoseconds.

Function Documentation

◆ rcutils_system_time_now()

rcutils_ret_t rcutils_system_time_now ( rcutils_time_point_value_t now)

This function returns the time from a system clock. The closest equivalent would be to std::chrono::system_clock::now();

The resolution (e.g. nanoseconds vs microseconds) is not guaranteed.

The now argument must point to an allocated rcutils_time_point_value_t object, as the result is copied into this variable.


Attribute Adherence
Allocates Memory No
Thread-Safe Yes
Uses Atomics No
Lock-Free Yes
Parameters
[out]nowa datafield in which the current time is stored
Returns
RCUTILS_RET_OK if the current time was successfully obtained, or
RCUTILS_RET_INVALID_ARGUMENT if any arguments are invalid, or
RCUTILS_RET_ERROR an unspecified error occur.

◆ rcutils_steady_time_now()

rcutils_ret_t rcutils_steady_time_now ( rcutils_time_point_value_t now)

Retrieve the current time as a rcutils_time_point_value_t object.

This function returns the time from a monotonically increasing clock. The closest equivalent would be to std::chrono::steady_clock::now();

The resolution (e.g. nanoseconds vs microseconds) is not guaranteed.

The now argument must point to an allocated rcutils_time_point_value_t object, as the result is copied into this variable.


Attribute Adherence
Allocates Memory No
Thread-Safe Yes
Uses Atomics No
Lock-Free Yes
Parameters
[out]nowa struct in which the current time is stored
Returns
RCUTILS_RET_OK if the current time was successfully obtained, or
RCUTILS_RET_INVALID_ARGUMENT if any arguments are invalid, or
RCUTILS_RET_ERROR an unspecified error occur.