Getter function to return values of a struct in c-CodePudding

I'm practicing c and I want to return data of a struct to access it within an other location.

Let's say I have something like this:

typedef struct
{
    int8    x;    
    u64     y;     
    u32     z;   
} myData_t;


myData_t myData_g;


/*Setter*/
void WritemyData(const myData_t* data)
{
    myData_g = *data;
}

How can I return the data which are stored within a global variable to be read within an other location. Can I not just do something like:

/*Getter*/
myData_t GettmyData(void)
{
    return myData_g;
}

Would be thankful for any information!

CodePudding user response：

First of all, for things like this consider making the "global" a private variable instead, by adding static myData_t myData_g;. Now nobody outside this .c file can access it intentionally/by accident.

As for your function GettmyData, it will work fine. However, passing/returning structs by value is considered bad practice since it involves making a full copy of the struct on the stack, which may be slow and take up unnecessary memory temporarily.

This might be better idea might be:

void get_my_data (myData_t* obj)
{
  *obj = myData_g;
}

Here you have to document that the caller should allocate the variable pointed at by obj on the caller side.