pTAL Reference Manual (H06.08+)

Statements
HP pTAL Reference Manual—523746-006
12-11
CALL
param-name
is a variable identifier or an expression that defines an actual parameter to pass to
a formal parameter declared in identifier.
param-pair
is an actual parameter pair to pass to a formal parameter pair declared in
identifier. param-pair has the form:
string
is an expression of the type STRING . or STRING .EXT.
length
is an INT expression that specifies the length, in bytes, of string.
Use the CALL statement to call procedures and subprocedures (but usually not
functions).
To call functions, you usually use their identifiers in expressions. If you call a function
by using a CALL statement, the caller does not use the returned value of the function.
Actual parameters are value or reference parameters and are optional or required
depending on the formal parameter specification in the called procedure or
subprocedure declaration (described in Section 14, Procedures, Subprocedures, and
Procedure Pointers). A value parameter passes the content of a location; a reference
parameter passes the address of a location.
In a CALL statement to a VARIABLE procedure or subprocedure or to an
EXTENSIBLE procedure, you can omit optional parameters in two ways:
•
You can omit parameters or parameter pairs unconditionally. Use an empty comma
for each omitted parameter or parameter pair up to the last specified parameter or
parameter pair. If you omit all parameters, you can specify an empty parameter list
(parentheses with no commas) or you can omit the parameter list altogether.
•
You can omit parameters or parameter pairs conditionally. Use the $OPTIONAL
built-in routine as described in Section 15, Built-In Routines.
After the called procedure or subprocedure completes execution, control returns to the
statement following the CALL statement that calls the procedure or subprocedure.
string length :
VST039.vsd