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Rules 16-2-3

Posted: Tue Feb 05, 2019 3:52 am
by nishiyama
Rules 16-2-3 Rationale has the following description.

If this multiple inclusion leads to multiple or conflicting definitions,
then this can result in undefined or erroneous behaviour.

I understood that it would be a multiple definition.

However, I do not understand the case of conflicting definition.
What kind of cases are there?

Re: Rules 16-2-3

Posted: Fri Feb 08, 2019 7:27 am
by dg1980

i believe if you follow rule 3-2-3 strictly it is impossible to have conflicting definitions (because linker does not check types in different translation units).
If you need more background google "C traps and pitfalls" by Koenig and check chapter 3.1.

Re: Rules 16-2-3

Posted: Wed Apr 10, 2019 2:55 pm
by misra cpp
We agree with dg1980. Strict adherence to 3-2-3 ensures conflicting definitions will not occur. Requiring include guards ensures that, for headers at least, 3-2-3 will be observed