The GLOBAL clause specifies that a data-name is available to every program contained within the program that declares it, as long as the contained program does not itself have a declaration for that name. All data-names subordinate to or condition-names or indexes associated with a global name are global names.
A data-name is global if the GLOBAL clause is specified either in the data description entry by which the data-name is declared or in another entry to which that data description entry is subordinate. The GLOBAL clause can be specified in the working-storage section, the file section, the linkage section, and the local-storage section, but only in data description entries whose level-number is 01.
In the same data division, the data description entries for any two data items for which the same data-name is specified must not include the GLOBAL clause.
A statement in a program contained directly or indirectly within a program that describes a global name can reference that name without describing it again.
Two programs in a run unit can reference common data in the following circumstances: