c++ - cannot convert '<brace-enclosed initializer list>' to 'double' in return -

i'm writing arduino program in c++ , have following question:

why work

double* getarray() {   double p, r, y;    double ret[3] = {p, r, y};   return ret; } 

but doesn't

double* getarray() {   double p, r, y;    return {p, r, y}; } 

neither of code blocks work.

the first 1 compiles introduces undefined behavior return pointer array no longer exist. detailed answer on please see can local variable's memory accessed outside scope?

the second code block fails compile {p, r, y} not valid initializer double*.

what need here std::vector<double>, std::array<double, some_constant_size> or std::unique_ptr<double[]>. if cannot use of need dynamically create array , need remember delete array when don like

double* getarray() {     double * arr = new double[3]{1,2,3};     return arr; }  int main() {     double* foo = getarray();     // use array here     delete [] foo; }