FreeBSD Manual Pages
NAME ck_pr_fence_load_atomic -- enforce ordering of load operations to atomic read-modify-write operations LIBRARY Concurrency Kit (libck, -lck) SYNOPSIS #include <ck_pr.h> void ck_pr_fence_load_atomic(void); void ck_pr_fence_strict_load_atomic(void); DESCRIPTION This function enforces the ordering of any memory load and ck_pr_load(3) operations with respect to store operations relative to the invocation of the function. Any store operations that were commit- ted on remote processors and received by the calling processor before the invocation of ck_pr_fence_load_atomic() is also be made visible only after a call to the ck_pr_fence_load family of functions. This function always serves as an implicit compiler barrier. On architec- tures with CK_MD_TSO or CK_MD_PSO specified (total store ordering and partial store ordering respectively), this operation only serves as a compiler barrier and no fence instructions will be emitted. To force the unconditional emission of a load fence, use ck_pr_fence_strict_load_atomic(). Architectures implementing CK_MD_RMO always emit a fence. EXAMPLE #include <ck_pr.h> static unsigned int a; static unsigned int b; void function(void) { unsigned int snapshot_a, snapshot_b; snapshot_a = ck_pr_load_uint(&a); /* * Guarantee that the load from "a" completes * before the update to "b". */ ck_pr_fence_load_atomic(); ck_pr_fas_uint(&b, 1); return; } RETURN VALUES This function has no return value. SEE ALSO ck_pr_stall(3), ck_pr_fence_atomic(3), ck_pr_fence_atomic_store(3), ck_pr_fence_atomic_load(3), ck_pr_fence_load_depends(3), ck_pr_fence_load_store(3), ck_pr_fence_store(3), ck_pr_fence_memory(3), ck_pr_barrier(3), ck_pr_fas(3), ck_pr_load(3), ck_pr_store(3), ck_pr_faa(3), ck_pr_inc(3), ck_pr_dec(3), ck_pr_neg(3), ck_pr_not(3), ck_pr_add(3), ck_pr_sub(3), ck_pr_and(3), ck_pr_or(3), ck_pr_xor(3), ck_pr_cas(3), ck_pr_btc(3), ck_pr_bts(3), ck_pr_btr(3) Additional information available at http://concurrencykit.org/ May 18, 2013 CK_PR_FENCE_LOAD_ATOMIC(3)
NAME | LIBRARY | SYNOPSIS | DESCRIPTION | EXAMPLE | RETURN VALUES | SEE ALSO
Want to link to this manual page? Use this URL:
<https://man.freebsd.org/cgi/man.cgi?query=ck_pr_fence_load_atomic&sektion=3&manpath=FreeBSD+Ports+14.3.quarterly>