C - is an indeterminate value indeterminable?

Question

According to this post an indeterminate value is:

3.17.2
1 indeterminate value
either an unspecified value or a trap representation

Accordi

Answer 1

The authors of the Standard recognized that there are some cases where it might be expensive for an implementation to ensure that code that reads an indeterminate value won't behave in ways that would be inconsistent with the Standard (e.g. the value of a uint16_t might not be in the range 0..65535. While many implementations could cheaply offer useful behavioral guarantees about how indeterminate values behave in more cases than the Standard requires, variations among hardware platforms and application fields mean that no single set of guarantees would be optimal for all purposes. Consequently, the Standard simply punts the matter as a Quality of Implementation issue.

The Standard would certainly allow a garbage-quality-but-conforming implementation to treat almost any use of e.g. an uninitialized uint16_t as an invitation to release nasal demons. It says nothing about whether high-quality implementations that are suitable for various purposes can do likewise (and still be viewed as high-quality implementations suitable for those purposes). If one is needs to accommodate implementations that are designed to trap on possible unintended data leakage, one may need to explicitly clear objects in some cases where their value will ultimately be ignored but where the implementation couldn't prove that it would never leak information. Likewise if one needs to accommodate implementations whose "optimizers" are designed on the basis of what low-quality-but-conforming implementations are allowed to do, rather than than what high-quality general-purpose implementations should do, such "optimizers" may make it necessary to add otherwise-unnecessary code to clear objects even when code doesn't care about the value (thus reducing efficiency) in order to avoid having the "optimizers" treat the failure to do so as an invitation to behave nonsensically.