LANG.STRUCT.DEF.MULTIEXT : Multiple External

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LANG.STRUCT.DEF.MULTIEXT : Multiple External Definitions

An identifier with external linkage has more than one associated definition.

Class Name

Multiple External Definitions

Significance

style

Mnemonic

LANG.STRUCT.DEF.MULTIEXT

Categories

MisraC2023	MisraC2023:8.6	An identifier with external linkage shall have exactly one external definition
Misra2012	Misra2012:8.6	An identifier with external linkage shall have exactly one external definition
Misra2004	Misra2004:8.9	An identifier with external linkage shall have exactly one external definition
AUTOSARC++14	AUTOSARC++14:M3-2-2	The One Definition Rule shall not be violated.
	AUTOSARC++14:M3-2-4	An identifier with external linkage shall have exactly one definition.
MisraC++2008	MisraC++2008:3-2-2	The One Definition Rule shall not be violated.
	MisraC++2008:3-2-4	An identifier with external linkage shall have exactly one definition.
MisraC++2023	MisraC++2023:6.2.1	The one-definition rule shall not be violated
	MisraC++2023:6.2.3	The source code used to implement an entity shall appear only once

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
INCREMENTAL_BUILD = No
WARNING_FILTER += allow class="Multiple External Definitions"

Note that retaining the unnormalized ASTs will increase the disk space used to store the project representation, and may make the analysis take longer.

Incrementality Note: This warning class is not available for incremental analyses, even if the class is explicitly enabled.

Suppose the project consists of LANG.STRUCT.DEF.MULTIEXT.a.c, LANG.STRUCT.DEF.MULTIEXT.b.c, and LANG.STRUCT.DEF.MULTIEXT.c.c.

/* LANG.STRUCT.DEF.MULTIEXT.b.c */

extern int i_onedef;
extern int i_twodef;
extern int f_onedef( int i);
extern int f_twodef( int i);

/* LANG.STRUCT.DEF.MULTIEXT.b.c */

int i_twodef = 3;
int f_twodef( int i){return i;}

/* LANG.STRUCT.DEF.MULTIEXT.c.c */

int i_onedef = 7;                                       /* only definition of i_onedef */
int i_twodef = 8;               /* 'Multiple External Definitions'  warning issued here */ 
int f_onedef( int i){return i;}                         /* only definition of f_onedef() */
int f_twodef( int i){return i;} /* 'Multiple External Definitions' warning issued here
                                 * (even though the two definitions are identical) */

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

LANG.STRUCT.DEF.MULTIEXT : Multiple External Definitions

Summary

Properties

Example

Relevant Configuration File Parameters