## 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;

**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 Control Chart Behavior by Using Implicit Events)`change(true);`

`chg(false);`

Indexing into a vector or matrix (see Operations for Vectors and Matrices in Stateflow)

`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.

### 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`

.

**Note**

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.

**Note**

If you define `t`

as a Stateflow data object, your custom definition of `t`

overrides the
built-in value.