| SC_BARRIER(2) | SC_BARRIER(2) | 
#include <sc.h>
int sc_barrier( void );
sc_barrier() must be called on all nodes to get a successful 
return. When the program running on all nodes reaches the point where
sc_barrier(), then all sc_barrier() function
calls returns.
sc_barrier() returns 0 if it succeeds
or returns the following error number:
EINTR