* Oleg: > I have a code where i need more than one "wrong" pointer value(this one is > NULL pointer). Something like a signal handler SIG_IGN that equal to 1. > > So, my question is, what is the guarantied range of addresses (from 0 to X), > which can be safely used for this purpose on any hardware architecture? On most architectures, -1L to -4095L is reserved for error numbers returned by the mmap system call. But mmap is a bit special in that pointer must be page-aligned, so that this might not be of much help.
