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The compiler issues warnings at the end of the procedure where the record variables are defined, that is, when some of the fields are definitely not set. However, no warnings are issued if fields are used in the source before they are initialized, as the control flow may be different.

In some cases, it is not possible to determine at compile time whether the fields have actually been initialized. For example:

•For the array variable V, whose elements are records, if any assignment of the kind V[i]:= X or V[i].F:= Y occurs, the compiler considers the corresponding fields of V[i] for all values of i to be initialized. If such a field is used, but not set, it is denoted as V[...].F in the warning message.

•All formal parameters are assumed to be initialized. Consequently, the compiler does not perform any checking for these component fields.

With the -Rwoption, the compiler takes into account built-in procedures which initialize their argument variables, for example, reset(f) for the file buffer variable f^ and its components. rewrite(f) does not initialize f^. The compiler also examines field handling inside WITH statements.

Use the -Rwoption to check the use of “unsafe” variant records, such as the assignment of a variant to a field, or the use of another field from a “parallel” variant. These practices may result in runtime errors which are hard to find.

Note – The -Rwoption requires extra compile-time, and is, therefore, recommended for use in debugging only.

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Pascal 4.0 User’s Guide