__INSN_BARRIER(3) BSD Library Functions Manual __INSN_BARRIER(3)NAME
__insn_barrier — compiler reorder barrier
SYNOPSIS
#include <sys/cdefs.h>
void
__insn_barrier();
DESCRIPTION
The __insn_barrier() macro prevents GCC from moving code across the bar‐
rier. In other words, the compiler is not allowed to reorder read and
write commands below the barrier with the code preceding the barrier.
Like with the volatile type qualifier, __insn_barrier() may be necessary
in some corner cases to prevent the compiler from misoptimizing.
SEE ALSOgcc(1), cdefs(3), mb(9)
Paul E. McKenney, Memory Barriers: a Hardware View for Software Hackers,
http://www.rdrop.com/users/paulmck/scalability/paper/whymb.2010.06.07c.pdf,
June 7, 2010.
HISTORY
The __insn_barrier() macro first appeared in NetBSD 2.0.
BSD January 2, 2011 BSD