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?RCS: $Id: d_sync_atomic.U 167 2013-05-08 17:58:00Z rmanfredi $
?RCS:
?RCS: Copyright (c) 2011, Raphael Manfredi
?RCS:
?RCS: You may redistribute only under the terms of the Artistic License,
?RCS: as specified in the README file that comes with the distribution.
?RCS: You may reuse parts of this distribution only within the terms of
?RCS: that same Artistic License; a copy of which may be found at the root
?RCS: of the source tree for dist 4.0.
?RCS:
?MAKE:d_sync_atomic: Trylink cat
?MAKE: -pick add $@ %<
?S:d_sync_atomic:
?S: This variable conditionally defines the HAS_SYNC_ATOMIC symbol, which
?S: indicates to the C program that __sync_xxx() atomic operations are
?S: made available by the compiler.
?S:.
?C:HAS_SYNC_ATOMIC:
?C: This symbol, if defined, indicates that __sync_xxx() atomic operations
?C: are made available by the compiler, namely __sync_synchronize() to
?C: issue a memory barrieer, __sync_bool_compare_and_swap() for issuing a
?C: test-and-set and __sync_fetch_and_add() for atomic increases of values.
?C:.
?H:#$d_sync_atomic HAS_SYNC_ATOMIC /**/
?H:.
?LINT:set d_sync_atomic
: check for __sync_synchronize and friends
$cat >try.c <<EOC
int main(void)
{
static int ret;
int i;
__sync_synchronize();
ret |= __sync_bool_compare_and_swap(&i, 0, 1);
ret += __sync_fetch_and_add(&i, 1);
return ret;
}
EOC
cyn="whether atomic memory operations are possible"
set d_sync_atomic
eval $trylink
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