Library subroutines operate the same way as ESL subroutines. Argument list parameters must be specified as variables when the library subroutine is called, since subroutines return values through their parameters. The type and number of arguments after the subroutine name must match the type and number of arguments in the declaration.

To invoke a library subroutine from your ESL program, use the call statement. The call statement syntax is the same for ESL and library subroutines:

call SUB_NAME(ARG1,ARG2,...)

where SUB_NAME is the identifier for a previously defined subroutine.