C and C++


LANG.STRUCT.CGEN.MND : Missing Non-default Association in C Generic

Summary

The association list for a C generic selection expression contains only a default association.

Generic selection is not useful in this case, because the default association is always used.

Properties

Class Name Missing Non-default Association in C Generic
Significance redundancy
Mnemonic LANG.STRUCT.CGEN.MND
Categories
MisraC2023 MisraC2023:23.3 A generic selection should contain at least one non-default association
Misra2012 Misra2012:23.3 A generic selection should contain at least one non-default association
Availability Available for C only (not C++).
Enabling Checks for this warning class are disabled by default, and require the unnormalized C ASTs for the project. To enable them, add the following WARNING_FILTER rule and RETAIN_UNNORMALIZED_C_AST specification to the project configuration file.
RETAIN_UNNORMALIZED_C_AST = Yes
WARNING_FILTER += allow class="Missing Non-default Association in C Generic"
Note that retaining the unnormalized ASTs will increase the disk space used to store the project representation, and may make the analysis take longer.

Example

#define MND_DEFAULT_ONLY(y) (_Generic(y, default: 2000))  /* this could be expressed more clearly as
                                                           * #define MND_DEFAULT_ONLY(y) 2000
                                                           */
#define MND_DEFAULT_AND_NONDEFAULT(y) (_Generic(y, int: 5, float: 6, default: 2000))
#define MND_NONDEFAULT_ONLY(y) (_Generic(y, int: 5, float:6))

int lang_struct_cgen_mnd(void){
    int rv = 10;
    rv += MND_DEFAULT_ONLY(20); /* 'Missing Non-default Association in C Generic' warning issued here */
    rv += MND_DEFAULT_AND_NONDEFAULT(20);                                  /* ok */
    rv += MND_NONDEFAULT_ONLY(20);                                         /* ok */
    return rv;
}

Relevant Configuration File Parameters

The following configuration file parameters affect checks for this warning class.