If the Extra Commas option is on, the compiler generates a warning when it encounters an extra comma. For example, this statement is legal in C, but it causes a warning when this option is on:

int a[] = { 1, 2, 3, 4, }; // ^ WARNING: Extra comma after 4

The Extra Commas option corresponds to the pragma warn_extracomma, described at "warn_extracomma." To check whether this option is on, use __option (warn_extracomma). See "Checking Options" for information on how to use this directive.