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Remove trace point in simulation debugging session


untrace blk removes the trace point for the block blk from the list of trace points for the current simulation debugging session. The software displays information about the block that corresponds to a trace point each time the block executes in the simulation debugging session.

  • When you start the simulation debugging session programmatically, the information is displayed in the MATLAB® Command Window.

  • When you start the simulation debugging session using the Simulink® Editor, the information is displayed in the Diagnostic Viewer.

You can use this function in a simulation debugging session started:

  • Interactively, using the Simulink Toolstrip

  • Programmatically, using the sldebug function

  • Programmatically, using the sim function with the 'debug' name-value argument


This function is available only for simulation debugging sessions started programmatically and for interactive simulation debugging sessions while paused within a time step.

Input Arguments

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Block that corresponds to trace point to remove, specified using one of these options:

  • (t)s:b — Block ID where t is the index of the task in which the block executes, s is the index of the system that contains the block, and b is the index of the block within the system

  • gcb — Current block


To start a simulation debugging session interactively, add one or more breakpoints to your model, and in the Breakpoints List, check that Pause within time step is selected. When the simulation pauses on a breakpoint, some of the programmatic debugging commands, such as the stop command, are available for use in the MATLAB Command Window.

Version History

Introduced before R2006a

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