ERROR_HWNDS_HAVE_DIFF_PARENT - 1441 (0x5A1)
All handles to windows in a multiple-window position structure must have the same parent.
Updated: Feb 21, 2026
Technical Meaning
This error indicates that a function or API call encountered an issue where multiple window handles in a structure were expected to have the same parent, but they did not. This is a parameter validation error.
Error Details
The Windows API requires that all windows represented by handles within a single multiple-window position structure must share the same parent window. If this condition is not met, the function will return this specific error code.
Usage Context
This error typically occurs when using functions such as SetWindowSubclass or other APIs that manage window relationships and require consistency in the hierarchy of windows.
Developer Interpretation
Developers should ensure that all handles passed to a function expecting multiple window positions are derived from the same parent window. Failure to do so will result in this error being returned, indicating an invalid parameter.
Related Errors
- ERROR_INVALID_PARAMETER (1208): A generic error for invalid parameters.
- ERROR_WINDOW_NOT_FOUND (1436): An error related to a specific window not existing or having the expected properties.
FAQ
Q: What does this error mean?
A: This error indicates that multiple windows in a structure do not share the same parent, violating API requirements for consistency in window hierarchy.
Q: How can I avoid this error?
A: Ensure all handles passed to functions expecting multiple window positions are derived from the same parent window.
Summary
The ERROR_HWNDS_HAVE_DIFF_PARENT (1441) is a specific parameter validation error indicating that multiple windows in a structure do not share the same parent. Developers must ensure consistency in the hierarchy of windows to avoid this error.