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Supported Symbols in Actions

Boolean Symbols, true and false

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

cooling_fan = true;
heating_fan = false;


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.


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

Comment Symbols, %, //, /*

Use the symbols %, //, and /* to represent comments 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 Model Configuration Parameters: Comments (Simulink Coder). C chart 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.

Hexadecimal Notation Symbols, 0xFF

C charts support C style hexadecimal notation, for example, 0xFF. You can use hexadecimal values wherever you can use decimal values.

Infinity Symbol, inf

Use the MATLAB® symbol inf to represent infinity in C charts. Calculations like n/0, where n is any nonzero real value, result in inf.


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

Line Continuation Symbol, ...

Use the characters ... at the end of a line 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;

MATLAB Display Symbol, ;

Omitting the semicolon after an expression displays the results of the expression in the Diagnostic Viewer. If you use a semicolon, the results do not appear.

Single-Precision Floating-Point Number Symbol, F

Use a trailing F to specify single-precision floating-point numbers in C charts. 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.

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.


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