Code Generation for Enumerations
Enumerations represent a fixed set of named values.Enumerations help make your MATLAB®code and generated C/C++ code more readable. For example, the generated code can test equality with code such asif (x == Red)
instead of usingstrcmp
.To generate C/C++ code, you must have万博1manbetx®Coder™.
When you use enumerations in aMATLAB Function
block, adhere to these restrictions:
Calls to methods of enumeration classes are not supported.
Passing strings or character vectors to constructors of enumerations is not supported.
For aMATLAB Functionblock, you can import an externally defined type by using
Simulink.defineIntEnumType
or you can define an enumeration class. The enumeration class must derive from one of these base types:Simulink.IntEnumType
,int8
,uint8
,int16
,uint16
, orint32
. SeeDefine Enumerations for MATLAB Function Blocks.You can use only a limited set of operations on enumerations. SeeAllowed Operations on Enumerations.
Use enumerations with functions that support enumerated types for code generation. SeeMATLAB Toolbox Functions That Support Enumerations.
Define Enumerations forMATLAB FunctionBlocks
You can define enumerations forMATLAB Functionblocks in two ways:
To import an externally defined enumeration, use the
Simulink.defineIntEnumType
function. SeeImport Enumerations Defined Externally to MATLAB.In a class definition file, define an enumerated type. For example:
classdef PrimaryColors <
Simulink.IntEnumType
枚举红(1),蓝色(2),黄色(4)结束
If you define an enumerated type in a class definition file, the class must derive from one of these base types:Simulink.IntEnumType
,int8
,uint8
,int16
,uint16
, orint32
. Then, you can exchange enumerated data betweenMATLAB Functionblocks and other Simulink blocks in a model.
If you useSimulink Coderto generate C/C++ code, you can use the enumeration class base type to control the size of an enumerated type in generated C/C++ code. You can:
Represent an enumerated type as a fixed-size integer that is portable to different targets.
Reduce memory usage.
Interface with legacy code.
Match company standards.
The base type determines the representation of the enumerated type in generated C/C++ code.
If the base type isSimulink.IntEnumType
, the code generator produces a C enumeration type. Consider the following MATLAB enumerated type definition:
classdefLEDcolor < Simulink.IntEnumTypeenumerationGREEN(1), RED(2)endend
This enumerated type definition results in the following C code:
typedef enum { GREEN = 1, RED } LEDcolor;
typedef
statement for the enumerated type and#define
枚举值的语句。考虑到following MATLAB enumerated type definition:classdefLEDcolor < int16enumerationGREEN(1), RED(2)endend
typedef int16_T LEDcolor; #define GREEN ((LEDcolor)1) #define RED ((LEDcolor)2)
To customize the code generated for an enumerated type, seeCustomize Simulink Enumeration.
Allowed Operations on Enumerations
For code generation, you are restricted to the operations on enumerations listed in this table.
Operation | Example | Notes |
---|---|---|
assignment operator: |
xon = LEDcolor.GREEN xoff = LEDcolor.RED |
— |
relational operators: |
xon == xoff |
Code generation does not support using |
cast operation |
double(LEDcolor.RED) |
— |
conversion to character array or string |
y = char(LEDcolor.RED); y1 = cast(LEDcolor.RED,'char'); y2 = string(LEDcolor.RED); |
|
indexing operation |
m = [1 2] n = LEDcolor(m) p = n(LEDcolor.GREEN) |
— |
control flow statements: if, switch, while |
if state == sysMode.ON led = LEDcolor.GREEN; else led = LEDcolor.RED; end |
— |
MATLABToolbox Functions That Support Enumerations
For code generation, you can use enumerations with these MATLAB toolbox functions: