0029935: Foundation Classes - introduce OSD_ThreadPool class defining a thread pool

New class OSD_ThreadPool has been introduced to define a Thread Pool for multi-threading algorithm.
Thread Pool assigns a serial number for each thread allowing Multi-Threading algorithm to allocate thread-local storage variables as an array whose size is the same as the number of threads.

OSD_ThreadPool also redirects exceptions to a thread calling parallel execution and consistently initializes FPE exception handling.

New class Standard_Condition provides a platform-independent  tool similar to Event in WinAPI.

A new auxiliary function Standard_Atomic_CompareAndSwap() has been introduced
for performing atomic compare and swap of integer number.
Standard_Atomic_Increment/Standard_Atomic_Decrement fallback implementation
using ASM code for x86 processors for GCC has been dropped;
instead, it is expected that GCC should be properly configured targeting modern x86 architectures.

OSD_Signal now declares fFltExceptions as thread_local variable accessible through OSD::ToCatchFloatingSignals() property.
Standard_THREADLOCAL macro (wrapping thread_local attribute) has been moved to public header Standard_Macro.hxx.

OSD_Parallel::ForEach() has been extended with new optional parameter theNbItems and uses OSD_ThreadPool::DefaultPool().

src/BRepMesh/BRepMesh_FastDiscret.cxx

@@ -120,7 +120,7 @@ void BRepMesh_FastDiscret::Perform(const TopoDS_Shape& theShape)
     aFaces.push_back(aFace);
   }
 
-  OSD_Parallel::ForEach(aFaces.begin(), aFaces.end(), *this, !myParameters.InParallel);
+  OSD_Parallel::ForEach(aFaces.begin(), aFaces.end(), *this, !myParameters.InParallel, (Standard_Integer )aFaces.size());
 }
 
 

src/BRepMesh/BRepMesh_IncrementalMesh.cxx

@@ -234,7 +234,7 @@ void BRepMesh_IncrementalMesh::update()
     update(aFaceIt.Value());
 
   // Mesh faces
-  OSD_Parallel::ForEach(myFaces.begin(), myFaces.end(), *myMesh, !myParameters.InParallel);
+  OSD_Parallel::ForEach(myFaces.begin(), myFaces.end(), *myMesh, !myParameters.InParallel, myFaces.Size());
 
   commit();
   clear();