COBOL Manual for TNS/E Programs (H06.08+, J06.03+)

• Correspondence of Formal and Actual Parameters
The formal parameters in the USING phrase of the Procedure Division header and the actual
parameters in the USING phrase of the CALL statement correspond by position, not by name.
• Declaration Locations and Access Modes of Formal and Actual Parameters
You must declare formal parameters in the Linkage Section. Every parameter has a 32-bit
address. If you specify STANDARD access mode, the ECOBOL compiler ignores it and issues
a warning.
• Parameter Validation
The ECOBOL compiler reports errors if the number of actual parameters (in the CALL statement)
differs from the number of formal parameters (in the Procedure Division heading).
The HP COBOL compilers report errors under these conditions:
◦ The type (alphanumeric, numeric, and so on) of an actual parameter differs from that of
its corresponding formal parameter.
◦ The size of an actual parameter differs from that of its corresponding formal parameter.
• Passing Index Values
You cannot pass an index-name (defined by the INDEXED phrase of an OCCURS clause) as
a parameter because it is not a level 01, level 77, or elementary data item. You can pass an
index value in an index data item (defined by a USAGE INDEX clause) as a parameter, but
there is no correspondence between the index-name used with the table in the calling program
and the index-name used with the table in the called program. Index-names in the called and
calling program always refer to separate data areas.
• Recursion
Although called programs can contain CALL statements, a called program cannot call itself
explicitly or implicitly.
• Calling and Called Program Using the Same File
A called program does not inherit access to an internal file opened by its caller. A calling
program and a called program can operate on records of the same file in these ways:
◦ One of the programs does all the reading and writing and passes the data items as
parameters to the other.
◦ Each program opens the file as an internal file with a separate file connector.
◦ The file name has the GLOBAL attribute.
◦ The file is declared in any program and is given the EXTERNAL attribute. Then the file
belongs to the run unit, and any program in the run unit that declares the same file with
the EXTERNAL attribute can share in its manipulation.
• Difference Between X/Open CALL Statement and ENTER Statement
The X/Open CALL statement reports an error if the types of the actual and formal parameters
do not match; the ENTER statement attempts to convert the actual parameters into the types
of the formal parameters.
CALL 299