LANG.PREPROC.UMIF : Undefined Macro in #if

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An identifier in the controlling expression of a preprocessor #if or #elif statement has not been previously defined with #define.

Class Name

Undefined Macro in #if

Significance

style

Mnemonic

LANG.PREPROC.UMIF

Categories

MisraC2023	MisraC2023:20.9	All identifiers used in the controlling expression of #if or #elif preprocessing directives shall be #define'd before evaluation
Misra2012	Misra2012:20.9	All identifiers used in the controlling expression of #if or #elif preprocessing directives shall be #define'd before evaluation
Misra2004	Misra2004:19.11	All macro identifiers in preprocessor directives shall be defined before use, except in #ifdef and #ifndef preprocessor directives and the defined() operator
AUTOSARC++14	AUTOSARC++14:M16-0-7	Undefined macro identifiers shall not be used in #if or #elif pre-processor directives, except as operands to the defined operator.
MisraC++2008	MisraC++2008:16-0-7	Undefined macro identifiers shall not be used in #if or #elif preprocessor directives, except as operands to the defined operator.
MisraC++2023	MisraC++2023:19.1.3	All identifiers used in the controlling expression of #if or #elif preprocessing directives shall be #define'd at the point of evaluation

Availability

Available for C and C++.

Enabling

Checks for this warning class are disabled by default. To enable them, add the following WARNING_FILTER rule to the project configuration file.

WARNING_FILTER += allow class="Undefined Macro in #if"

For the sake of this example, we assume that THREE and FOUR are not defined at an earlier point in the program, or in the build command.

#define ONE 1
#define TWO 2

#if TWO > ONE                                /* both identifiers are defined macros */
/* ... */
#endif 

#if THREE > ONE /* 'Undefined Macro in #if' warning issued here: THREE not defined. */
/* ... */                                     
#endif

#if FOUR > ONE  /* 'Undefined Macro in #if' warning issued here: FOUR defined, but not until later. */
/* ... */                                     
#endif
#define FOUR 4

#if 2 > 1                                    /* no identifiers */
/* ... */
#endif

static int two=2;
#if two > ONE   /* 'Undefined Macro in #if' warning issued here: two not defined with #define */
/* ... */
#endif

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

LANG.PREPROC.UMIF : Undefined Macro in #if

Summary

Properties

Example

Relevant Configuration File Parameters