Typedef struct not working

Question

I made this simple code but I'm getting the following error

exit status 1
'RGB' does not name a type

typedef struct
RGB
{
        double r;
        double g;
        double b;
};

RGB led;

RGB func(){
  RGB temp;
  return RGB;
}

I am not getting the error on "RGB led" but just on the function. Does anyone know a solution for this? Thanks!

The typedef syntax is "typedef [known type] [new name];" so RGB would go after the closing brace of the structure definition. Or see @edgarbonet's post for another alternative. — JRobert
– JRobert, Commented Mar 12, 2020 at 15:11

Edgar Bonet · Accepted Answer · 2020-03-12 09:35:06Z

In plain C, structs are identified by "struc tags", which do not live in the same namespace as type names. Thus, if you declare

struct RGB {
    ...
};

a variable of this type should be declared as

struct RGB led;

In order to avoid the inconvenience of repeatedly typing struct, a common idiom is to define it as a type:

typedef struct {
    ...
} RGB;

RGB led;

The Arduino environment, however, is based on the C++ programming language. In C++ struct tags are types, and you thus do not need the typedef:

struct RGB {
    ...
};

RGB led;

This is the recommended idiom in C++: just remove the typedef.

fabianoriccardi · Accepted Answer · 2020-03-12 09:28:12Z

1

There are 2 errors:

you are returning a class type, and not the temp object

  RGB func(){
    RGB temp;
    return RGB; --> return temp;
  }

To use your typedef you should put the struct "name" after the braced parenthesis:

typedef struct
{
    double r;
    double g;
    double b;
} RGB;

answered Mar 12, 2020 at 9:28

fabianoriccardi

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2 Answers 2