There are some nasty semantic questions associated with the proper return value for snprintf. BSD4.4 snprintf()s return the number of characters they would have written had the buffer been infinite. This is despite the manual page saying they return the number of characters actually written. Number of characters written does not include the NULL. GNU snprintf()s return the number of characters actually written (minus the NULL). On a overflowed buffer, the GNU documentation conflicts with itself. At one point it says, (bufsiz - 1) is returned, and in another example it says (bufsiz) is returned (but (bufsiz - 1) plus a NULL character are written). I'm not sure what it does for real. I've seen a few other cobbled version of *nprintf. I'm best off with a dart board if I needed to apriori determine what they do on the boundary cases. Some important boundary cases: vsnprintf (buf, bufsiz, fmt, ap) bufsiz = 0 bufsiz = 1 bufsiz = amount of chars sprint will use, less one for the null bufsiz = amount of chars sprint will use, no room for null bufsiz = less than amount of chars sprint will use Which return values of -1, 0, bufsiz - 1, bufsiz, or >bufsiz (heaven forbid a core dump)? Do they write on buf[bufsiz]? What do they write to buf? What is the state of NULL terminatation on each of the sitations above? Many different answers have I seen. For those of you working on syslog patches using *nprintf, you will do the world a favor if you make it explicitly clear the semantics you expect. Dave Morrison dmorriso@us.oracle.com