It's not new, it has been in GCC for quite a number of years (not sure how to check this quickly).
UPDATE: I found a list (https://ohse.de/uwe/articles/gcc-attributes.html#func-format) that says format was added in GCC 2.3-3.4 (whatever the range means). GCC 3.4.0 was released on April 18 2004. Now I'm sad I didn't say "ten years" above, as my original hunch was. :)
It's not new, it has been in GCC for quite a number of years (not sure how to check this quickly).
UPDATE: I found a list (https://ohse.de/uwe/articles/gcc-attributes.html#func-format) that says format was added in GCC 2.3-3.4 (whatever the range means). GCC 3.4.0 was released on April 18 2004. Now I'm sad I didn't say "ten years" above, as my original hunch was. :)