ERROR_SEM_IS_SET - 102 (0x66)
The semaphore is set and cannot be closed.
Updated: Feb 21, 2026
Technical Meaning
The ERROR_SEM_IS_SET error code indicates that a semaphore has been set and cannot be closed. This typically occurs when the semaphore is in a state where it cannot be released or closed due to ongoing operations or conditions.
Error Details
This error is specific to semaphore management within the Windows operating system. Semaphores are synchronization objects used for managing access to shared resources, ensuring that multiple threads or processes do not interfere with each other.
When a semaphore is set and cannot be closed, it means that there are still active operations dependent on this semaphore, preventing its closure. This can lead to resource management issues if the semaphore remains in an uncontrolled state for an extended period.
Usage Context
This error code is relevant in scenarios where semaphores are used for synchronization purposes, such as in multithreaded applications or when managing access to shared resources across processes.
Developer Interpretation
Developers should interpret this error as a signal that the current operation involving the semaphore cannot proceed due to its set state. This may require adjusting the operation context or ensuring that all dependent operations have completed before attempting to close the semaphore.
Related Errors
ERROR_SEM_NOT_FOUND(108, 0x6C): Indicates that a specified semaphore does not exist.ERROR_INVALID_PARAMETER(1258, 0x4E6): Occurs when an invalid parameter is passed to the function.ERROR_TOO_MANY_SEMAPHORES(107, 0x6B): Suggests that too many semaphores are in use or have been created.
FAQ
Q: What does ERROR_SEM_IS_SET mean?
A: It indicates that a semaphore is set and cannot be closed due to ongoing operations.
Q: How can I handle this error?
A: Ensure all dependent operations have completed before attempting to close the semaphore. Adjust operation context as necessary.
Summary
The ERROR_SEM_IS_SET error code signifies an issue with a semaphore that is in a set state and cannot be closed, which may impact resource management in multithreaded or process synchronization scenarios. Developers should carefully manage semaphore states to avoid such issues.