what for(;;); ?

Projects Programming
1

Hi

I found this command : for(;;);
in this program:

if (!SD.begin(chipSelect)) {
Serial.println("Erreur de carte SD !");
for(;;);
}

I don't understand this command : for(;;);
Usually i use return

Is it better than return(for void) ??

thanks

2

It is an infinite loop, just "hangs".

3

I found this command : for(;;);

I very much doubt it.

You probably found

for(;;);

Note how the use of code tags stops some parts of code being interpreted as HTML commands

Please use them in future when posting code

4 
  for (A ; B ; C) D;

is roughly equivalent to:

  A;
  while (B)
  {
    D;
    C;
  }

The 'for' loop can have a missing 'B' but you can't have a "while ()" (syntax error) and treating a missing 'B' as 'false' would mean that the loop would never happen (which is useless) so they treat a missing 'B' as 'true'

The special case of:

  for (;;);

is roughly equivalent to:

  while (true);

In other words: an infinite loop that does nothing.

5

In other words: an infinite loop that does nothing.

Or everything.

Used in C as the equivalent of the Arduino loop() function.

loop() {
//Your code here
}

Is the same as:

for (;;) {
//Your code here
}
6

PerryBebbington:
Or everything.
Used in C as the equivalent of the Arduino loop() function.

Indeed. Look at how loop() is implemented in the core:

	for (;;) {
		loop();
		if (serialEventRun) serialEventRun();
	}
7

Yes, it's for(;;); like the subject

thank you all, i understand better now. :slight_smile:

8

fcfranck:
Yes, it's for(;;); like the subject

thank you all, i understand better now. :slight_smile:

...except for the part about how to use code tags, reply #2