Mention that these functions aren't standard. OK?
Index: lib/libc/gen/err.3 =================================================================== RCS file: /cvs/src/lib/libc/gen/err.3,v retrieving revision 1.20 diff -u -p -r1.20 err.3 --- lib/libc/gen/err.3 23 Apr 2014 16:26:33 -0000 1.20 +++ lib/libc/gen/err.3 14 Sep 2016 07:28:26 -0000 @@ -189,6 +189,10 @@ if ((fd = open(block_device, O_RDONLY, 0 .Xr perror 3 , .Xr printf 3 , .Xr strerror 3 +.Sh STANDARDS +These functions are +.Bx +extensions. .Sh HISTORY The functions .Fn err , -- Michal Mazurek
