SetLastErrorEx function (winuser.h)

Sets the last-error code.

Currently, this function is identical to the SetLastError function. The second parameter is ignored.


void SetLastErrorEx(
  [in] DWORD dwErrCode,
  [in] DWORD dwType


[in] dwErrCode

The last-error code for the thread.

[in] dwType

This parameter is ignored.

Return value



The last-error code is kept in thread local storage so that multiple threads do not overwrite each other's values.

Most functions call SetLastError or SetLastErrorEx only when they fail. However, some system functions call SetLastError or SetLastErrorEx under conditions of success; those cases are noted in each function's documentation.

Applications can optionally retrieve the value set by this function by using the GetLastError function immediately after a function fails.

Error codes are 32-bit values (bit 31 is the most significant bit). Bit 29 is reserved for application-defined error codes; no system error code has this bit set. If you are defining an error code for your application, set this bit to indicate that the error code has been defined by the application and to ensure that your error code does not conflict with any system-defined error codes.


Requirement Value
Minimum supported client Windows XP [desktop apps only]
Minimum supported server Windows Server 2003 [desktop apps only]
Target Platform Windows
Header winuser.h (include Windows.h)
Library User32.lib
DLL User32.dll

See also

Error Handling Functions


Last-Error Code