The GetThreadPriority function returns the priority value for the specified thread. This value, together with the priority class of the thread’s process, determines the thread’s base-priority level.
int GetThreadPriority(
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HANDLE hThread |
// handle to thread |
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); |
Windows NT: The handle must have THREAD_QUERY_INFORMATION access. For more information, see Thread Objects.
If the function succeeds, the return value is the thread’s priority level.
If the function fails, the return value is THREAD_PRIORITY_ERROR_RETURN. To get extended error information, call GetLastError.
The thread’s priority level is one of the following values:
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Priority |
Meaning |
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THREAD_PRIORITY_ABOVE_NORMAL | |
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Indicates 1 point above normal priority for the priority class. | |
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THREAD_PRIORITY_BELOW_NORMAL | |
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Indicates 1 point below normal priority for the priority class. | |
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THREAD_PRIORITY_HIGHEST | |
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Indicates 2 points above normal priority for the priority class. | |
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THREAD_PRIORITY_IDLE | |
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Indicates a base-priority level of 1 for IDLE_PRIORITY_CLASS, NORMAL_PRIORITY_CLASS, or HIGH_PRIORITY_CLASS processes, and a base-priority level of 16 for REALTIME_PRIORITY_CLASS processes. | |
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THREAD_PRIORITY_LOWEST | |
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Indicates 2 points below normal priority for the priority class. | |
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THREAD_PRIORITY_NORMAL | |
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Indicates normal priority for the priority class. | |
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THREAD_PRIORITY_TIME_CRITICAL | |
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Indicates a base-priority level of 15 for IDLE_PRIORITY_CLASS, NORMAL_PRIORITY_CLASS, or HIGH_PRIORITY_CLASS processes, and a base-priority level of 31 for REALTIME_PRIORITY_CLASS processes. |
Every thread has a base-priority level determined by the thread’s priority value and the priority class of its process. The operating system uses the base-priority level of all executable threads to determine which thread gets the next slice of CPU time. Threads are scheduled in a round-robin fashion at each priority level, and only when there are no executable threads at a higher level will scheduling of threads at a lower level take place.
For a table that shows the base-priority levels for each combination of priority class and thread priority value, refer to the SetPriorityClass function.