Compiler error. Problem with class declaration

Projects Programming
1

I don’t know why I get this error.

/Users/dannyswarzman/Documents/Arduino/Test/Test.ino:24:5: error: request for member 'PP' in 'm', which is of non-class type 'MM()'
24 | m.PP();
| ^~
exit status 1

Compilation error: request for member 'PP' in 'm', which is of non-class type 'MM()'

class MM
{
  public:
    MM(){}
    void PP();
};

void MM::PP()
{
  {Serial.println("MM");}
}
MM m();
#include <arduino.h>
void setup() {
  Serial.begin(115200);
  while(!Serial)
    delay(10);
  Serial.println("Begin");

  if(m)
    Serial.println ("m is");
  else
    Serial.println("m isn't");
  m.PP();
}

void loop() {
}

The error message is for the last line of setup().

2

Show the verbose error log in code tags, there is often more information

3

When declaring the global m, omit the paranetheses.

#include <arduino.h> will fail on case sensitive OSes, and in any case is included too late to be able to use Serial in class MM.

Declaring m as a global variable means it's not a pointer. So testing if it's not NULL is not correct.

class MM {
 public:
   MM() {}
   void PP();
};

void MM::PP() {
   { Serial.println("MM"); }
}

MM m;

void setup() {
   Serial.begin(115200);
   while( !Serial )
      delay(10);
   Serial.println("Begin");

   m.PP();
}

void loop() {
}

or, if you're commited to the idea of testing m being non NULL, make it a pointer.

class MM {
 public:
   MM() {}
   void PP();
};

void MM::PP() {
   { Serial.println("MM"); }
}

MM *m = new MM;

void setup() {
   Serial.begin(115200);
   while( !Serial )
      delay(10);
   Serial.println("Begin");

   if( m )
      Serial.println("m is");
   else
      Serial.println("m isn't");
   m->PP();
}

void loop() {
}
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