Threads can be created in the suspended state and then started later. If a thread is in the suspended state, then the call to start the thread executing is ResumeThread.
It takes the handle of the thread as a parameter. There is a SuspendThread call that will cause a running thread to be suspended. This call is expected to be used only by tools such as debugger. Suspending a running thread may lead to problems if the thread currently holds resources such as mutexes. The following code demonstrates the creation of a suspended thread and then calling ResumeThread on that thread. The code uses a call to getchar , which waits for the enter key to be pressed, to separate the creation of the thread from the act of resuming thread:.
The suspended state of the thread is handled as a counter, so multiple calls to SuspendThread need to be matched with multiple calls to ResumeThread. Each thread of execution has associated with it a suspend count. If this count is zero, then the thread is not suspended. If it is nonzero, the thread is in a suspended state. Each call to SuspendThread increments the suspend count.
Each call to ResumeThread decrements the suspend count. A suspended thread will resume only when its suspend count has reached zero. Therefore, to resume a suspended thread implies that there must be the same number of calls to ResumeThread as there have been calls to SuspendThread. Many of the Windows API functions return handles. As we saw from the earlier discussion of type casting, these are really just unsigned integers.
However, they have a particular purpose. Windows API calls that return handles have actually caused a resource to be created within the kernel space.
The handle is just an index for that resource. When the application has finished with the resource, the call to CloseHandle enables the kernel to free the associated kernel space resources. Resources with handles can be shared between processes. Once a resource exists, other processes can open a handle to that resource or duplicate an existing handle to the resource. It is important to know that the handle of a kernel resource makes sense only within the context of the process that has access to the resource.
Passing the value of the handle to another process does not enable the other process to get access to the resource. The kernel needs to enable access to the resource and provide a new handle for the existing resource in the new process. Some functions do not return a handle.
For these functions, there is no associated kernel resource. So, it is not necessary to call CloseHandle once the resource is no longer needed. Toggle navigation BogoToBogo. As a result, make sure to test before executing the command with a high number of threads. Once you complete the steps, you will notice that copying files and folders will take significantly less time.
You are not limited to copying files and folders to an external or internal drive, and this also works to migrate files over the network. We hate spam as much as you! Unsubscribe any time Powered by follow. Tweet Share Submit. How to use multi-threaded feature with Robocopy To use the Robocopy multithreaded feature to copy files and folders to another drive faster, use these steps: Open Start on Windows Ask a question.
Quick access. Search related threads. Remove From My Forums. Answered by:. Archived Forums. Common Language Runtime Internals and Architecture. NET, including security, performance, hosting, base classes, interop, reliability, debugging, GC, and profiling. Sign in to vote. Hi, I am trying to implement a multithreaded windows service using c and.
I have a few components which I would like to have running simultaneously -- Main Windows Service Coordinates threads and service settings stored in the database and polled every so often as defined in the settings, db info is hardcoded MySQL Database Connector Multiple components will need to access various parts of the database and I would like to send all db access through a single instance of this class running on its own thread.
Thank you, Philip Heath.
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