cilk_sync

The keyword name is _Cilk_sync. The header file <cilk/cilk.h> defines macros that provide names with simpler conventions (in this case, cilk_sync). This document uses the names as defined in cilk.h.

The cilk_sync statement indicates that the current function cannot continue in parallel with its spawned children. After the children all complete, the current function can continue.

The syntax is as follows:

cilk_sync;

cilk_sync only syncs with children spawned by this function. Children of other functions are not affected.

There is an implicit cilk_sync at the end of every function and every try block that contains a cilk_spawn. The sync is needed for these reasons:

• To ensure that program resource use does not grow out of proportion to the program's parallelism.

• To ensure that a race-free parallel program has the same behavior as the corresponding serial program. An ordinary non-spawn call to a function works the same regardless of whether the called function spawns internally.

• There will be no strands left running that might have side effects or fail to free resources.

• The called function will have completed all operations when it returns.

The implicit cilk_sync occurs after destructors are invoked.