SetLastErrorEx

The SetLastErrorEx function sets the last-error code.

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

VOID SetLastErrorEx(
  DWORD dwErrCode,  // per-thread error code
  DWORD dwType      // error type
);

Parameters

dwErrCode

[in] Specifies the last-error code for the thread.

dwType

This parameter is ignored.

Return Values

This function does not return a value.

Remarks

Error codes are 32-bit values (bit 31 is the most significant bit). Bit 29 is reserved for application-defined error codes; no Win32 API 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.

This function is intended primarily for dynamic-link libraries (DLL). Calling this function after an error occurs allows the DLL to emulate the behavior of the Win32 API.

Most Win32 functions call SetLastError when they fail. Function failure is typically indicated by a return value error code such as zero, NULL, or –1. Some functions call SetLastError under conditions of success; those cases are noted in each function's reference topic.

Applications can retrieve the value saved by this function by using the GetLastError function.

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

Requirements

  Windows NT/2000: Requires Windows NT 3.1 or later.
  Windows 95/98: Requires Windows 95 or later.
  Header: Declared in Winuser.h; include Windows.h.
  Library: Use User32.lib.

See Also

Error Handling Overview, Error Handling Functions, GetLastError