Pro*C examples: printf question

[Quoted] Some of Oracle's Pro*C demo programs, such as sqlvcp.pc, contain a printf flag that I've never seen before. In the following statment:

printf("%.*s\n", msg_len, err_msg);

what is the '.' flag for? It's not documented in any of my C manuals.

--
Chuck Hamilton
chuckh_at_dvol.com

If at first you don't succeed, skydiving isn't for you.