| /////////////////////////////////////////////////////////////////////////// |
| // |
| // Copyright (c) 2005, Industrial Light & Magic, a division of Lucas |
| // Digital Ltd. LLC |
| // |
| // All rights reserved. |
| // |
| // Redistribution and use in source and binary forms, with or without |
| // modification, are permitted provided that the following conditions are |
| // met: |
| // * Redistributions of source code must retain the above copyright |
| // notice, this list of conditions and the following disclaimer. |
| // * Redistributions in binary form must reproduce the above |
| // copyright notice, this list of conditions and the following disclaimer |
| // in the documentation and/or other materials provided with the |
| // distribution. |
| // * Neither the name of Industrial Light & Magic nor the names of |
| // its contributors may be used to endorse or promote products derived |
| // from this software without specific prior written permission. |
| // |
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| // |
| /////////////////////////////////////////////////////////////////////////// |
| |
| #ifndef INCLUDED_ILM_THREAD_H |
| #define INCLUDED_ILM_THREAD_H |
| |
| //----------------------------------------------------------------------------- |
| // |
| // class Thread |
| // |
| // Class Thread is a portable interface to a system-dependent thread |
| // primitive. In order to make a thread actually do something useful, |
| // you must derive a subclass from class Thread and implement the |
| // run() function. If the operating system supports threading then |
| // the run() function will be executed int a new thread. |
| // |
| // The actual creation of the thread is done by the start() routine |
| // which then calls the run() function. In general the start() |
| // routine should be called from the constructor of the derived class. |
| // |
| // The base-class thread destructor will join/destroy the thread. |
| // |
| // IMPORTANT: Due to the mechanisms that encapsulate the low-level |
| // threading primitives in a C++ class there is a race condition |
| // with code resembling the following: |
| // |
| // { |
| // WorkerThread myThread; |
| // } // myThread goes out of scope, is destroyed |
| // // and the thread is joined |
| // |
| // The race is between the parent thread joining the child thread |
| // in the destructor of myThread, and the run() function in the |
| // child thread. If the destructor gets executed first then run() |
| // will be called with an invalid "this" pointer. |
| // |
| // This issue can be fixed by using a Semaphore to keep track of |
| // whether the run() function has already been called. You can |
| // include a Semaphore member variable within your derived class |
| // which you post() on in the run() function, and wait() on in the |
| // destructor before the thread is joined. Alternatively you could |
| // do something like this: |
| // |
| // Semaphore runStarted; |
| // |
| // void WorkerThread::run () |
| // { |
| // runStarted.post() |
| // // do some work |
| // ... |
| // } |
| // |
| // { |
| // WorkerThread myThread; |
| // runStarted.wait (); // ensure that we have started |
| // // the run function |
| // } // myThread goes out of scope, is destroyed |
| // // and the thread is joined |
| // |
| //----------------------------------------------------------------------------- |
| |
| #include "IlmBaseConfig.h" |
| |
| #if defined _WIN32 || defined _WIN64 |
| #ifdef NOMINMAX |
| #undef NOMINMAX |
| #endif |
| #define NOMINMAX |
| #include <windows.h> |
| #include <process.h> |
| #elif HAVE_PTHREAD |
| #include <pthread.h> |
| #endif |
| |
| #if defined(OPENEXR_DLL) && !defined(ZENO_STATIC) |
| #ifdef ILMTHREAD_EXPORTS |
| #define ILMTHREAD_EXPORT __declspec(dllexport) |
| #else |
| #define ILMTHREAD_EXPORT __declspec(dllimport) |
| #endif |
| #else |
| #define ILMTHREAD_EXPORT |
| #endif |
| |
| namespace IlmThread { |
| |
| // |
| // Query function to determine if the current platform supports |
| // threads AND this library was compiled with threading enabled. |
| // |
| |
| ILMTHREAD_EXPORT bool supportsThreads (); |
| |
| |
| class ILMTHREAD_EXPORT Thread |
| { |
| public: |
| |
| Thread (); |
| virtual ~Thread (); |
| |
| void start (); |
| virtual void run () = 0; |
| |
| private: |
| |
| #if defined _WIN32 || defined _WIN64 |
| HANDLE _thread; |
| #elif HAVE_PTHREAD |
| pthread_t _thread; |
| #endif |
| |
| void operator = (const Thread& t); // not implemented |
| Thread (const Thread& t); // not implemented |
| }; |
| |
| |
| } // namespace IlmThread |
| |
| #endif |