Learn more about Stateflow

Symbols in Action Language

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Boolean Symbols, true and false Comment Symbols, %, //, /* Hexadecimal Notation Symbols, 0xFF Infinity Symbol, inf Line Continuation Symbol, ... Literal Code Symbol, $ MATLAB Display Symbol, ; Single-Precision Floating-Point Number Symbol, F Time Symbol, t

Boolean Symbols, true and false

Use the symbols true and false to represent Boolean constants in Stateflow action language. You can use these symbols as scalars in expressions. Examples include:

cooling_fan = true;
heating_fan = false;

Tip   These symbols are case-sensitive. Therefore, TRUE and FALSE are not Boolean symbols.

Do not use true and false in the following cases. Otherwise, error messages appear.

• Left-hand side of assignment statements

  • true++;

  • false += 3;

  • [true, false] = my_function(x);

• Argument of the change implicit event (see Using Implicit Events)

  • change(true);

  • chg(false);

• Indexing into a vector or matrix (see How to Assign and Access Values of Vectors and Matrices)

  • x = true[1];

  • y = false[1][1];

Note   If you define true and false as Stateflow data objects, your custom definitions of true and false override the built-in Boolean constants.

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Comment Symbols, %, //, /*

Use the symbols %, //, and /* to represent comments in Stateflow action language as shown in these examples:

% MATLAB comment line
// C++ comment line
/* C comment line */

You can also include comments in generated code for an embedded target (see Real-Time Workshop Pane: Comments in the Real-Time Workshop Reference) or a Stateflow custom target (see Configuring a Custom Target). Stateflow action language comments in generated code use multibyte character code. Therefore, you can have code comments with characters for non-English alphabets, such as Japanese Kanji characters.

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Hexadecimal Notation Symbols, 0xFF

Stateflow action language supports C style hexadecimal notation, for example, 0xFF. You can use hexadecimal values wherever you can use decimal values.

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Infinity Symbol, inf

Use the MATLAB symbol inf to represent infinity in Stateflow action language. Calculations like n/0, where n is any nonzero real value, result in inf.

Note   If you define inf as a Stateflow data object, your custom definition of inf overrides the built-in value.

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Line Continuation Symbol, ...

Use the characters ... at the end of a line of action language to indicate that the expression continues on the next line. For example, you can use the line continuation symbol in a state action:

entry: total1 = 0, total2 = 0, ...
  total3 = 0;

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Literal Code Symbol, $

Use $ characters to mark action language that you want the parser to ignore but you want to appear in the generated code. For example, the parser does not process any text between the $ characters below.

$
ptr -> field = 1.0;
$

Note   Avoid frequent use of literal symbols.

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MATLAB Display Symbol, ;

Omitting the semicolon after an expression displays the results of the expression in the MATLAB Command Window. If you use a semicolon, the results do not appear.

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Single-Precision Floating-Point Number Symbol, F

Use a trailing F to specify single-precision floating-point numbers in Stateflow action language. For example, you can use the action statement x = 4.56F; to specify a single-precision constant with the value 4.56. If a trailing F does not appear with a number, double precision applies.

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Time Symbol, t

Use the letter t to represent absolute time that the chart inherits from a Simulink signal in simulation targets. For example, the condition [t - On_time > Duration] specifies that the condition is true if the difference between the simulation time t and On_time is greater than the value of Duration.

The letter t has no meaning for nonsimulation targets, since t depends on the specific application and target hardware.

Note   If you define t as a Stateflow data object, your custom definition of t overrides the built-in value.

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Using Operations in Actions

Calling C Functions in Actions

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