A COBOL program can call a subprogram that is linked into the same executable module as the caller (static linking) or that is provided in a shared library (dynamic linking). COBOL for AIX also provides for runtime resolution of a target subprogram from a shared library.
If you link a target program statically, it is part of the executable module of the caller and is loaded with the caller. If you link dynamically or resolve a call at run time, the target program is provided in a library and is loaded either when the caller is loaded or when the target program is called.
Either dynamic or static linking of subprograms is done for COBOL CALL literal. Runtime resolution is always done for COBOL CALL identifier and is done for CALL literal if the DYNAM option is in effect.
Restriction: You cannot mix 32-bit and 64-bit COBOL programs in an application. All program components within an application must be compiled using the same setting of the ADDR compiler option.
related references
ADDR
DYNAM
CALL statement (COBOL for AIX Language Reference)