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+--- Thread: Is CERT C FIO34-C really NOT covered by MISRA rules as stated in MISRA C:2012 Addendum 3 (/showthread.php?tid=1476)
Is CERT C FIO34-C really NOT covered by MISRA rules as stated in MISRA C:2012 Addendum 3 - alexporto - 28-02-2019
The document MISRA:C Addendum 3 classifies the CERT C rule FIO34-C as NOT COVERED by MISRA (Coverage is None/None)
However, the condition detailed in this rule FIO34-C seems to be fully covered by MISRA rule 22.7
FIO34-C: Distinguish between characters read from a file and EOF or WEOF
MISRA C:2012 Amendment 1, Rule 22.7: The macro EOF shall only be compared with the unmodified return value from any Standard Library function capable of returning EOF
Is that correct?
Re: Is CERT C FIO34-C really NOT covered by MISRA rules as stated in MISRA C:2012 Addendum 3 - misra-c - 13-06-2019
Both rules address the issue that a value returned by getchar ( and similar functions ) may be indistinguishable from EOF. However they cover different situations.
The description and examples of FIO34-C show that is concerned with the situation when int and char have the same size.
Rule 22.7 is concerned with situations where the return value undergoes a type conversion if that value is then compared to EOF.
The following example is non-compliant with FIO34-C, but compliant with rule 22.7 as no type conversions occur.
Code:
int c;
do {
c = getchar();
} while (c != EOF);