EXEC SQL BEGIN DECLARE SECTION;
char      comm[200];
char      street[30];
char      city[20];
a_sql_len cityind;
long      empnum;
EXEC SQL END DECLARE SECTION;

...
sprintf( comm, 
    "UPDATE %s SET Street = :?, City = :?"
    "WHERE EmployeeID = :?",
    tablename );
EXEC SQL PREPARE S1 FROM :comm FOR UPDATE;
EXEC SQL EXECUTE S1 USING :street, :city:cityind, :empnum;

EXEC SQL BEGIN DECLARE SECTION;
char comm[200];
EXEC SQL END DECLARE SECTION;
...
sprintf( comm, 
    "UPDATE %s SET Street = :street, City = :city"
   " WHERE EmployeeID = :empnum",
   tablename );
EXEC SQL PREPARE S1 FROM :comm FOR UPDATE;
/* Assume that there are no more than 10 host variables. 
 * See next example if you cannot put a limit on it. */
sqlda = alloc_sqlda( 10 ); 
EXEC SQL DESCRIBE BIND VARIABLES FOR S1 INTO sqlda;
/* sqlda->sqld will tell you how many 
   host variables there were. */
/* Fill in SQLDA_VARIABLE fields with 
   values based on name fields in sqlda. */
...
EXEC SQL EXECUTE S1 USING DESCRIPTOR sqlda;
free_sqlda( sqlda );