Visible to Intel only — GUID: GUID-131470E9-282C-444E-B31E-0F8E51D4F748
Package Contents
Parallelizing Simple Loops
Parallelizing Complex Loops
Parallelizing Data Flow and Dependence Graphs
Work Isolation
Exceptions and Cancellation
Containers
Mutual Exclusion
Timing
Memory Allocation
The Task Scheduler
Design Patterns
Migrating from Threading Building Blocks (TBB)
Constrained APIs
Invoke a Callable Object
Appendix A Costs of Time Slicing
Appendix B Mixing With Other Threading Packages
References
parallel_for_each Body semantics and requirements
parallel_sort ranges interface extension
TBB_malloc_replacement_log Function
Parallel Reduction for rvalues
Type-specified message keys for join_node
Scalable Memory Pools
Helper Functions for Expressing Graphs
concurrent_lru_cache
task_group extensions
The customizing mutex type for concurrent_hash_map
Visible to Intel only — GUID: GUID-131470E9-282C-444E-B31E-0F8E51D4F748
Catching Exceptions Inside the Node that Throws the Exception
If you catch an exception within the node’s body, execution continues normally, as you might expect. If an exception is thrown but is not caught before it propagates beyond the node’s body, the execution of all of the graph’s nodes are canceled and the exception is rethrown at the call site of graph::wait_for_all(). Take the graph below as an example:
graph g;
function_node< int, int > f1( g, 1, []( int i ) { return i; } );
function_node< int, int > f2( g, 1,
[]( const int i ) -> int {
throw i;
return i;
} );
function_node< int, int > f3( g, 1, []( int i ) { return i; } );
make_edge( f1, f2 );
make_edge( f2, f3 );
f1.try_put(1);
f1.try_put(2);
g.wait_for_all();
In the code above, the second function_node, f2, throws an exception that is not caught within the body. This will cause the execution of the graph to be canceled and the exception to be rethrown at the call to g.wait_for_all(). Since it is not handled there either, the program will terminate. If desirable, the exception could be caught and handled within the body:
function_node< int, int > f2( g, 1,
[]( const int i ) -> int {
try {
throw i;
} catch (int j) {
cout << "Caught " << j << "\n";
}
return i;
} );
If the exception is caught and handled in the body, then there is no effect on the overall execution of the graph. However, you could choose instead to catch the exception at the call to wait_for_all:
try {
g.wait_for_all();
} catch ( int j ) {
cout << "Caught " << j << "\n";
}
In this case, the execution of the graph is canceled. For our example, this means that the input 1 never reaches f3 and that input 2 never reaches either f2 or f3.