[Bug c++/50423] error: ‘getpid’ was not declared in this scope

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50423

--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> 2011-09-16 
09:34:31 UTC ---
As documented at http://gcc.gnu.org/gcc-4.7/changes.html

"Avoid polluting the global namespace by inclusion of <unistd.h>."