parameters as host variables

I think I must be missing something obvious, but I can not seem to let procedure parameters be used as host variables in esql programs, e.g., void foo(a,b) EXEC SQL BEGIN DECLARE SECTION; long int a; long int b; EXEC SQL END DECLARE SECTION; { EXEC SQL UPDATE mytable SET mycolumn = :a WHERE myindex = :b; } This seems to work fine if I make everything a local variable: void foo(a,b) long int a; long int b; { EXEC SQL BEGIN DECLARE SECTION; long int locala = a; long int localb = b; EXEC SQL END DECLARE SECTION; EXEC SQL UPDATE mytable SET mycolumn = :locala WHERE myindex = :localb; } Am I missing something obvious? Thanks. -Mark (mss@transarc.com)