TIME-SYS

Overview

Provides time-related structures and functions.

Since:

1.0

Version:

1.0

Summary

Files

File Name

Description

time.h

Provides structures and functions related to the system time.

Data Structures

Data Structure Name

Description

timeval

Describes a period of time, accurate to microseconds.

timespec

Describes a period of time, accurate to nanoseconds.

itimerval

Describes a timer.

timezone

Describes a time zone.

Macros

Macro Name and Value

Description

ITIMER_REAL    0

Defines the timer that runs in real time.

Functions

Function Name

Description

gettimeofday (struct timeval __restrict value, void restrict ovalue)

int 

Obtains the system time and time zone.

getitimer (int w, struct itimerval old)

int 

Obtains the value of an intermittent timer.

setitimer (int w, const struct itimerval restrict value, struct itimerval __restrict ovalue)

int 

Sets the value for a timer.

settimeofday (const struct timeval tv, const struct timezone *tz)

int 

Sets the system time and time zone.

Details

Function Documentation

getitimer()

  1. int getitimer (int w, struct [itimerval]($api-api-SmartVision-Devices-itimerval.md) * old )

Description:

Obtains the value of an intermittent timer.

Parameters:

Name

Description
w Indicates the timer type. Only ITIMER_REAL is supported.
old Indicates the pointer to the timer value.

Returns:

Returns 0 if the operation is successful; returns -1 and sets errno to a value in the following table if the operation fails.

errno

Description

EINVAL

Incorrect input or timer type.

gettimeofday()

  1. int gettimeofday (struct [timeval]($api-api-SmartVision-Devices-timeval.md) *__restrict value, void *__restrict ovalue )

Description:

Obtains the system time and time zone.

Parameters:

Name

Description
value Indicates the pointer to the timeval structure that contains the time.
ovalue This parameter is used for compatibility only.

Attention:

Currently, there is no time zone structure. The return value of ovalue is empty.

Returns:

Returns 0 if the operation is successful; returns -1 and sets errno to a value in the following table if the operation fails.

errno

Description

EINVAL

Incorrect input.

setitimer()

  1. int setitimer (int w, const struct [itimerval]($api-api-SmartVision-Devices-itimerval.md) *__restrict value, struct [itimerval]($api-api-SmartVision-Devices-itimerval.md) *__restrict ovalue )

Description:

Sets the value for a timer.

Parameters:

Name

Description
w Indicates the timer type. Currently, only ITIMER_REAL is supported.
value Indicates the pointer to the timer value to set.
ovalue Indicates the pointer to the original timer value before the current setting, which can be NULL.

Returns:

Returns 0 if the operation is successful; returns -1 and sets errno to a value in the following table if the operation fails.

errno

Description

EINVAL

Incorrect input or timer type.

settimeofday()

  1. int settimeofday (const struct [timeval]($api-api-SmartVision-Devices-timeval.md) * tv, const struct [timezone]($api-api-SmartVision-Devices-timezone.md) * tz )

Description:

Sets the system time and time zone.

Parameters:

Name

Description
tv Indicates the pointer to the time to set.
tz Indicates the pointer to the time zone to set. This parameter is not used yet.

Attention:

tz is invalid. The time is set internally using clock_settime.

Returns:

Returns 0 if the operation is successful; returns -1 and sets errno to a value in the following table if the operation fails.

errno

Description

EINVAL

Incorrect input.