so this is a complete waste of time if forks > getpids.
and THREAD_GETMEM must allocate memory. so
the first call isn't exactly cheep. aren't they optimizing
for bad programming?
not only that, ... from getpid(2)
NOTES
Since glibc version 2.3.4, the glibc wrapper function for getpid()
caches PIDs, so as to avoid additional system calls when a process
calls getpid() repeatedly. Normally this caching is invisible, but its
correct operation relies on support in the wrapper functions for
fork(2), vfork(2), and clone(2): if an application bypasses the glibc
wrappers for these system calls by using syscall(2), then a call to
getpid() in the child will return the wrong value (to be precise: it
will return the PID of the parent process). See also clone(2) for dis-
- erik
