TRY..CATCH in T-SQL (sqlserver 2005)

SELECT * FROM sys.messages
ALTER  Procedure usp_sp1
@XMLData XML
AS
BEGIN
DECLARE
        ...declarations...
SET XACT_ABORT ON
BEGIN TRY
BEGIN TRANSACTION usp_sp1_tran
        ...transactions...
COMMIT TRANSACTION usp_sp1_tran
END TRY
BEGIN CATCH
        ROLLBACK TRAN usp_sp1_tran

        DECLARE @ErrorMessage NVARCHAR(4000)
           ,@ErrorNumber INT
           ,@ErrorSeverity INT
           ,@ErrorState INT
           ,@ErrorLine INT
           ,@ErrorProcedure NVARCHAR(200) ;

        SELECT  @ErrorNumber = ERROR_NUMBER()
               ,@ErrorSeverity = ERROR_SEVERITY()
               ,@ErrorState = ERROR_STATE()
               ,@ErrorLine = ERROR_LINE()
               ,@ErrorProcedure = ISNULL(ERROR_PROCEDURE(), '-') ;


        SELECT  @ErrorMessage = 'Procedure:' + @ErrorProcedure + '; Line:'
                + CAST(@ErrorLine AS VARCHAR(10)) + '; ' + ERROR_MESSAGE() ;

            --EXEC usp_Email @ErrorMessage, 'mymail@host.com'                     
        RAISERROR ( @ErrorMessage, 16, 1 )
END CATCH
END

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