SITENAME or DBSERVERNAME

If you use the SITENAME or DBSERVERNAME keyword as the default, the variable must be a CHAR, VARCHAR, NCHAR, NVARCHAR, or LVARCHAR data type. Its default value is the name of the database server at runtime. It is recommended that the size of the variable be at least 128 bytes long. You risk getting an error message during INSERT and ALTER TABLE operations if the length of the variable is too small to store the default value.

CREATE PROCEDURE gl_def()
   DEFINE GLOBAL gl_site CHAR(200) DEFAULT SITENAME;
   DEFINE GLOBAL gl_byte REFERENCES BYTE DEFAULT NULL;
   ...
END PROCEDURE