Function with passing a char variable and return of a logical variable

Projects Programming
1

Hello,

  1. I've defined a variable Host_001 in flash memory.
  2. with the bool PING(Host_001); - I call the function "bool PING(char Host)"
  3. but the function will not be executed (no print output)

Where is my mistake?

char Host[30];     
bool internet = false;               
const char Host_001[]PROGMEM = ("www.google.com");
int pingResult; 

void setup() {
Serial.begin(115200);
  while ((!Serial & millis()< 5000))   {
    ;               // wait for serial port 
  }

bool PING(Host_001);
    if (PING == true) {internet= true; Serial.println("o.k.");} else {internet= false;Serial.println("not  o.k.");} 
  }

void loop(){
delay(20000);
}
//**************************************************
bool PING(char Host) {   

  pingResult = 50;  // dummy result

  if (pingResult >= 0) {
    Serial.print(F("erfolgreich! RTT = "));
    Serial.print(pingResult);
    Serial.println(" ms");    
    return true;
  } else {
    Serial.print(F("FAILED! Error code: "));
    Serial.println(pingResult);   
    return false; 
  } 
}

I use a MKR1000.

2 
while ((!Serial & millis()< 5000))

Should be &&

bool PING(Host_001);

You didn't say what your sketch did output, but I'm guessing "o.k.". You are using a (non-zero) pointer value to initialise a variable PING of type bool. The variable PING with therefore always be true.

something like bool mypingresult = PING(Host_001); might be closer to what you want.

bool PING(char Host) {

The parameter doesn't have the correct pointer type.

3

I not sure, how should I changed the sketch? Sorry.
I changed the sketch: e.g. I 've added a '&' etc.

char Host[30];     
bool internet = false;               
const char Host_001[]PROGMEM = ("www.google.com");
int pingResult;     // RTT of the PING


void setup() {
Serial.begin(115200);
  while ((!Serial && millis()< 5000))   {
    ;               // wait for serial port to connect. Needed for native USB port only
  }
bool mypingresult = PING(Host_001);
    if (mypingresult) {internet= true; Serial.println("o.k.");} else {internet= false;Serial.println("not o.k.");} 
  }
void loop(){
delay(20000);
}
//***********************************************************************************************
bool PING(char Host) {     // 

  pingResult = 50;  // dummy result

  if (pingResult >= 0) {
    Serial.println(F("output 1"));
    return true;
  } else {
    Serial.println(F("output 2")); 
    return false; 
  } 
}

I ve got the following error messages:
error: invalid conversion from 'const char*' to 'char' [-fpermissive]
bool mypingresult = PING(Host_001);

initializing argument 1 of 'bool PING(char)' [-fpermissive]
bool PING(char Host) {

Correct pointer type?

4

Correct pointer type?

You are passing a string in PROGMEM to a function that expects a char in SRAM. Why?

5

Hoffmakl:
I ve got the following error messages:
error: invalid conversion from 'const char*' to 'char' [-fpermissive]
bool mypingresult = PING(Host_001);

initializing argument 1 of 'bool PING(char)' [-fpermissive]
bool PING(char Host) {

Correct pointer type?

The clue is in the error message...

6

PaulS:
You are passing a string in PROGMEM to a function that expects a char in SRAM. Why?

If I define "char Host_001[]" and assign a string to Host_001, then Host_001 is a string
and an array with multiple characters.

conclusion: Host is a string.

Thank you - the function is excecuted.