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CodeSonar® 9.2p0 CONFIDENTIAL CodeSecure Inc
C and C++

LANG.PREPROC.MARGME : Macro Argument is both Mixed and Expanded

Summary

A macro argument is subject to preprocessor expansion, and the corresponding macro parameter is "mixed use": it is used both in the body of the macro and separately as an operand to the # or ## operator.

See also:

Properties

Class Name Macro Argument is both Mixed and Expanded
Significance style
Mnemonic LANG.PREPROC.MARGME
Categories
MisraC2025 MisraC2025:20.10 The # and ## preprocessor operators should not be used
  MisraC2025:20.12 A macro parameter used as an operand to the # or ## operators, which is itself subject to further macro replacement, shall only be used as an operand to these operators
MisraC2023 MisraC2023:20.10 The # and ## preprocessor operators should not be used
  MisraC2023:20.12 A macro parameter used as an operand to the # or ## operators, which is itself subject to further macro replacement, shall only be used as an operand to these operators
Misra2012 Misra2012:20.10 The # and ## preprocessor operators should not be used
  Misra2012:20.12 A macro parameter used as an operand to the # or ## operators, which is itself subject to further macro replacement, shall only be used as an operand to these operators
Misra2004 Misra2004:19.13 The # and ## preprocessor operators should not be used
AUTOSARC++14 AUTOSARC++14:A16-0-1 The pre-processor shall only be used for unconditional and conditional file inclusion and include guards, and using the following directives: (1) #ifndef, (2) #ifdef, (3) #if, (4) #if defined, (5) #elif, (6) #else, (7) #define, (8) #endif, (9) #include.
  AUTOSARC++14:M16-3-2 The # and ## operators should not be used.
MisraC++2008 MisraC++2008:16-3-2 The # and ## operators should not be used.
MisraC++2023 MisraC++2023:19.3.1 The # and ## preprocessor operators should not be used
  MisraC++2023:19.3.3 The argument to a mixed-use macro parameter shall not be subject to further expansion
CWE CWE:710 Improper Adherence to Coding Standards
CERT-C CERT-C:PRE05-C Understand macro replacement when concatenating tokens or performing stringification
POW10 POW10:8 Limit the use of the preprocessor to file inclusion and simple macros.
JPL JPL:20 Make only very limited use of the C pre-processor.
Availability Available for C and 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="Macro Argument is both Mixed and Expanded"
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 

extern int dbg(int, char *);
#define STRINGY(X) (dbg(X, #X))         /* parameter X is mixed use */
                                        /* (will trigger 'Function-Like Macro', 'Macro Uses # Operator',
                                         *  and 'Use of #define' warnings if enabled)
                                         */
#define MULT4(X) ((X) * 4)              /* (will trigger 'Function-Like Macro' and 'Use of #define' warnings if enabled) */
#define LIMIT (1000 * 5)                /* (will trigger 'Use of #define' warning if enabled) */

void lang_preproc_margme(int param) {
    STRINGY(LIMIT);     /* 'Macro Argument is both Mixed and Expanded' warning issued here
                         * - parameter LIMIT is subject to preprocessor expansion
                         * - the corresponding STRINGIFY() parameter is "mixed use"
                         */
    STRINGY(param);                     /* ok: param is not subject to expansion */
    MULT4(LIMIT);                       /* ok: corresponding MULT4() parameter is not mixed use */
}

Relevant Configuration File Parameters

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

 

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