error_number

Is a user-defined error number larger than 50,000. The maximum value is 2147483647 (2^31 - 1).

' message '

Is a character string with a maximum of 2048 characters.

' severity '

Is one of three character strings: INFORMATIONAL, WARNING, or ERROR. severity is optional, with a default of INFORMATIONAL.

0 (success) or 1 (failure)

xp_logevent returns the following error message for the included code example:

The command(s) completed successfully.

When you send messages from Transact-SQL procedures, triggers, batches, and so on, use the RAISERROR statement instead of xp_logevent. xp_logevent does not call a message handler of a client or set @@ERROR. To write messages to the Windows Event Viewer and to the SQL Server error log file within an instance of SQL Server, execute the RAISERROR statement.

Requires membership in the db_owner fixed database role in the master database, or membership in the sysadmin fixed server role.

The following example logs the message, with variables passed to the message in the Windows Event Viewer.

DECLARE @@TABNAME varchar(30)
DECLARE @@USERNAME varchar(30)
DECLARE @@MESSAGE varchar(255)
SET @@TABNAME = 'customers'
SET @@USERNAME = USER_NAME()
SELECT @@MESSAGE = 'The table ' + @@TABNAME + ' is not owned by the user 
   ' + @@USERNAME + '.'

USE master
EXEC xp_logevent 60000, @@MESSAGE, informational

Reference