Colon (':')

Use the colon (':') to indicate a labeled statement:

start:
  x=0;
  ...
  goto start;

Special case of labels are case-labels, which are used in multiple selection statements, for example,

switch (a)
  {
    case 1:
      puts("One");
      break;
    case 2:
      puts("Two");
      break;
    ...
    default:
      puts("None of the above!");
  }

Note: The GNU C allows creating of local labels, which are useful in macro definitions.