Serial.read() always = -1 !

 hey !

my serial.read() equal -1. problem ?

this code:

code: [select]

void setup()
{
    serial.begin(9600);
}

void loop() {
 
  serial.println(serial.read());


}


 when start program , open "monitor serial"

serial.println(serial.read()) return -1 !

why ? can explain error pls ?


thanks ! 

-1 read returns when there's nothing there read.  use serial.available check if has been received before trying read serial line , read when there.

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