rosduration

Create a ROS duration object

Syntax

dur = rosduration

dur = rosduration(totalSecs)

dur = rosduration(secs,nsecs)

dur = rosduration (___,"DataFormat","struct")

Description

dur = rosduration returns a default ROS duration object. The properties for seconds and nanoseconds are set to 0.

Note

In a future release, ROS Toolbox will use message structures instead of objects for ROS messages.

To use message structures now, set the "DataFormat" name-value argument to "struct". For more information, see ROS Message Structures.

dur = rosduration(totalSecs) initializes the time values for seconds and nanoseconds based on totalSecs, which represents the time in seconds as a floating-point number.

dur = rosduration(secs,nsecs) initializes the time values for seconds and nanoseconds individually. Both inputs must be integers. Large values for nsecs are wrapped automatically with the remainder added to secs.

dur = rosduration (___,"DataFormat","struct") uses message structures instead of objects with any of the arguments in previous syntaxes. For more information, see ROS Message Structures.

Examples

Work with ROS Duration Objects

Create ROS Duration objects, perform addition and subtraction, and compare duration objects. You can also add duration objects to ROS Time objects to get another Time object.

Create a duration using seconds and nanoseconds.

dur1 = rosduration(100,2000000)

dur1 = 
  ROS Duration with properties:

     Sec: 100
    Nsec: 2000000

Create a duration using a floating-point value. This sets the seconds using the integer portion and nanoseconds with the remainder.

dur2 = rosduration(20.5)

dur2 = 
  ROS Duration with properties:

     Sec: 20
    Nsec: 500000000

Add the two durations together to get a single duration.

dur3 = dur1 + dur2

dur3 = 
  ROS Duration with properties:

     Sec: 120
    Nsec: 502000000

Subtract durations and get a negative duration. You can initialize durations with negative values as well.

dur4 = dur2 - dur1

dur4 = 
  ROS Duration with properties:

     Sec: -80
    Nsec: 498000000

dur5 = rosduration(-1,2000000)

dur5 = 
  ROS Duration with properties:

     Sec: -1
    Nsec: 2000000

Compare durations.

dur1 > dur2

ans = logical
   1

Initialize a ROS network.

rosinit

Launching ROS Core...
Done in 0.66173 seconds.
Initializing ROS master on http://172.23.70.204:50773.
Initializing global node /matlab_global_node_84293 with NodeURI http://dcc3148114glnxa64:35861/ and MasterURI http://localhost:50773.

Add a duration to a ROS Time object.

time = rostime('now','system')

time = 
  ROS Time with properties:

     Sec: 1.7694e+09
    Nsec: 597115993

timeFuture = time + dur3

timeFuture = 
  ROS Time with properties:

     Sec: 1.7694e+09
    Nsec: 99115993

Shut down the ROS network.

rosshutdown

Shutting down global node /matlab_global_node_84293 with NodeURI http://dcc3148114glnxa64:35861/ and MasterURI http://localhost:50773.
Shutting down ROS master on http://172.23.70.204:50773.

Input Arguments

totalSecs — Total time

0 (default) | scalar

Total time, specified as a floating-point scalar. The integer portion is set to the Sec property with the remainder applied to the Nsec property of the Duration object.

secs — Whole seconds

0 (default) | integer

Whole seconds, specified as an integer. This value is directly set to the Sec property of the Duration object.

Note

The maximum and minimum values for secs are [-2147483648, 2147483647].

nsecs — Nanoseconds

0 (default) | positive integer

Nanoseconds, specified as a positive integer. This value is directly set to the NSec property of the Duration object unless it is greater than or equal to 10⁹. The value is then wrapped and the remainders are added to the value of secs.

Output Arguments

dur — Duration

ROS Duration object | structure

Duration, returned as a ROS Duration object or message structure with fields Sec and NSec

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.

Version History

Introduced in R2019b

R2021a: ROS Message Structures

You can now create messages as structures with fields matching the message object properties. Using structures typically improves performance of creating, updating, and using ROS messages, but message fields are no longer validated when set. Message types and corresponding field values from the structures are validated when sent across the network.

To use ROS messages as structures, use the "DataFormat" name-value argument when creating your publishers, subscribers, or other ROS objects. Any messages generated from these objects will utilize structures.

pub = rospublisher("/scan","sensor_msgs/LaserScan","DataFormat","struct")
msg = rosmessage(pub)

You can also create messages as structures directly, but make sure to specify the data format as "struct" for the publisher, subscriber, or other ROS objects as well. ROS objects still use message objects by default.

msg = rosmessage("/scan","sensor_msgs/LaserScan","DataFormat","struct")
...
pub = rospublisher("/scan","sensor_msgs/LaserScan","DataFormat","struct")

In a future release, ROS messages will use structures by default and ROS message objects will be removed.

For more information, see Improve Performance of ROS Using Message Structures.