void

i thought that their only is void loop and void setup but when i got a code online i saw that their was a void Check_SMS(). what does this mean?

It means that there is a function named Check_SMS() and it is declared void to indicate that it does not return a value when called.

Somewhere in the code you saw there should be a call to the function like this

Check_SMS();

EDIT : corrected spelling

As noted, they are functions, not "voids". See:
https://www.arduino.cc/en/Reference/FunctionDeclaration

This comes up so often, maybe the Bare Minimum example should be:

#define FUNCTION_THAT_DOES_NOT_RETURN_A_VALUE void
FUNCTION_THAT_DOES_NOT_RETURN_A_VALUE setup() {
  // put your setup code here, to run once:


}


FUNCTION_THAT_DOES_NOT_RETURN_A_VALUE loop() {
  // put your main code here, to run repeatedly:


}

@johnwasser:

Then all the beginners would be writing "My FUNCTION_THAT_DOES_NOT_RETURN_A_VALUE loop doesn't work."

Are you sure you want that?

“How do I add a FUNCTION_THAT_DOES_NOT_RETURN_A_VALUE to my sketch?” might be slightly less annoying than “How do I add a void to my sketch?” I think it might be worth a try. :slight_smile: