I wanted to test my notion before presenting it, and it does turn out
that embedding an unreferenced value in a structure (COBOL record) at
least one other element of which is referenced in an executable
statement ensures that that structure will not be deleted.
A PL/I example
declare 1 copyright_block static,
2 false aligned bit initial('0'b),
2 true aligned bit initial('1'b),
2 copyright_text character(38) initial
('© copyright 1591 by John Harington, Kt') ;
found = false ; /* ex hyothesii */
linear_search: do i = lbound(A,1) to h bound(A,1) ;
. . .
found = (A(i) = s) ;
if found then leave ; /* match? */
. . .
end linear_search ;
Here the single reference to copyright_block.false in an executable
statement ensures that the structure copyright_block will not be
deleted (or trimmed) by an optimizing compiler.
The same scheme is usable mutatis mutandis in IBM C/C++ and COBOL.
John Gilmore, Ashland, MA 01721 - USA
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