esp8266/libraries/esp8266/examples/arduino_new/arduino_new.ino

// show arduino_new benefits
// released to public domain
// result is below

class SomeClass {
  public:
    SomeClass(const String& s1 = emptyString, const String& s2 = emptyString) {
      Serial.printf("SomeClass@%p(%s)(%s)\n", this, s1.c_str(), s2.c_str());
    }

    ~SomeClass() {
      Serial.printf("~ SomeClass @%p\n", this);
    }
};

class oom {
  private:
    char large [65000];
  public:
    oom() {
      Serial.printf("this constructor should not be called\n");
    }
};

void setup() {

  Serial.begin(115200);
  Serial.printf("\n\narduino_new benefits\n\n");
  delay(5000); // avoid too frequent bootloop

  // arduino_new / arduino_newarray api

  Serial.printf("\n----- arduino_new:\n");
  auto an = arduino_new(SomeClass);
  delete an;

  Serial.printf("\n----- arduino_new with oom:\n");
  auto anoom = arduino_new(oom);
  Serial.printf("nullptr: %p\n", anoom);
  delete anoom;

  Serial.printf("\n----- arduino_new with constructor parameters:\n");
  auto ancp = arduino_new(SomeClass, "param1", "param2");
  delete ancp;

  Serial.printf("\n----- arduino_newarray[2]\n");
  auto ana2 = arduino_newarray(SomeClass, 2);
  Serial.printf("@:%p s=%zd s(2)=%zd\n", ana2, sizeof(SomeClass), sizeof(SomeClass[2]));
  Serial.printf("0: %p\n", &ana2[0]);
  Serial.printf("1: %p\n", &ana2[1]);
  delete [] ana2;

  Serial.printf("\n----- arduino_newarray[2] (with constructor parameters)\n");
  auto ana2cp = arduino_newarray(SomeClass, 2, "param1");
  Serial.printf("@:%p s=%zd s(2)=%zd\n", ana2cp, sizeof(SomeClass), sizeof(SomeClass[2]));
  Serial.printf("0: %p\n", &ana2cp[0]);
  Serial.printf("1: %p\n", &ana2cp[1]);
  delete [] ana2cp;

  Serial.printf("\n----- arduino_newarray[100000]\n");
  auto anaX = arduino_newarray(SomeClass, 100000);
  Serial.printf("@:%p\n", anaX);

  // standard c++ api for new and new[]

  Serial.printf("\n----- new\n");
  auto sn = new SomeClass;
  delete sn;

  Serial.printf("\n----- new with oom: (abort() with option 'Exceptions: Disabled (new can abort)'\n");
  auto snoom = new oom;
  Serial.printf("nullptr: %p\n", snoom);
  delete snoom;

  Serial.printf("\n----- new[2]\n");
  auto sna2 = new SomeClass[2];
  Serial.printf("@:%p s=%zd s(2)=%zd\n", sna2, sizeof(SomeClass), sizeof(SomeClass[2]));
  Serial.printf("0: %p\n", &sna2[0]);
  Serial.printf("1: %p\n", &sna2[1]);
  delete [] sna2;

  Serial.printf("\n----- new[10000] (badly fails with 'Exceptions: Legacy' or '...Disabled'\n");
  auto snaX = new SomeClass[100000];
  Serial.printf("@:%p\n", snaX);
}

void loop() {
}

//////////////////////////////
/*

  Result with:
  Exceptions: Legacy(new can return nullptr)

  //////////////////////////////

  arduino_new benefits

  ----- arduino_new:
  SomeClass@0x3fff1864()()
  ~ SomeClass @0x3fff1864

  ----- arduino_new with oom:
  nullptr: 0

  ----- arduino_new with constructor parameters:
  SomeClass@0x3fff1864(param1)(param2)
  ~ SomeClass @0x3fff1864

  ----- arduino_newarray[2]
  SomeClass@0x3fff1868()()
  SomeClass@0x3fff1869()()
  @: 0x3fff1868 s = 1 s(2) = 2
  0: 0x3fff1868
  1: 0x3fff1869
  ~ SomeClass @0x3fff1869
  ~ SomeClass @0x3fff1868

  ----- arduino_newarray[2](with constructor parameters)
  SomeClass@0x3fff1868(param1)()
  SomeClass@0x3fff1869(param1)()
  @: 0x3fff1868 s = 1 s(2) = 2
  0: 0x3fff1868
  1: 0x3fff1869
  ~ SomeClass @0x3fff1869
  ~ SomeClass @0x3fff1868

  ----- arduino_newarray[100000]
  @: 0

  ----- new
  SomeClass@0x3fff1864()()
  ~ SomeClass @0x3fff1864

  ----- new with oom: (abort() with option 'Exceptions: Disabled (new can abort)'
  this constructor should not be called
  nullptr: 0

  ----- new[2]
  SomeClass@0x3fff1868()()
  SomeClass@0x3fff1869()()
  @:0x3fff1868 s = 1 s(2) = 2
  0: 0x3fff1868
  1: 0x3fff1869
  ~ SomeClass @0x3fff1869
  ~ SomeClass @0x3fff1868

  ----- new[10000](badly fails with 'Exceptions: Legacy' or '...Disabled'

  Exception(29):
  epc1 = 0x402013de epc2 = 0x00000000 epc3 = 0x00000000 excvaddr = 0x00000000 depc = 0x00000000

  >>> stack >>>
  ...

*/
/////////////////////////////