LANG.ID.ND.EXT : Non-distinct Identifiers: External Names

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CodeSonar^® 9.2p0

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C and C++

LANG.ID.ND.EXT : Non-distinct Identifiers: External Names

Summary

Two or more external identifiers are not distinct. The identifiers do not need to be declared in the same file.

Specifically, two or more identifiers have the same first N (case-sensitive) characters, where:

N depends on the setting of SIGNIFICANCE_LEN_EXTERN, and
all the identifiers have external linkage.

See Identifier Classes for related warning classes.

Properties

Class Name

Non-distinct Identifiers: External Names

Significance

style

Mnemonic

LANG.ID.ND.EXT

Categories

MisraC2025	MisraC2025:5.1	External identifiers shall be distinct
MisraC2023	MisraC2023:5.1	External identifiers shall be distinct
Misra2012	Misra2012:5.1	External identifiers shall be distinct
Misra2004	Misra2004:5.1	Identifiers (internal and external) shall not rely on the significance of more than 31 characters
CWE	CWE:710	Improper Adherence to Coding Standards
CERT-C	CERT-C:DCL23-C	Guarantee that mutually visible identifiers are unique
JSF++	JSF++:46	User-specified identifiers (internal and external) will not rely on significance of more than 64 characters.

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="Non-distinct Identifiers: External Names"

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.

Example

Suppose SIGNIFICANCE_LEN_EXTERN=-1.

/* pair 1: distinct in first 6 characters */
extern int okA;                      
extern int okB;     

/* pair 2:  distinct in first 31 characters; not distinct in first 6 characters
 *  - 'Non-distinct Identifiers: External Names' warning issued for C90 only */
extern int ok99onlyA; 
extern int ok99onlyB;    

/* pair 3:  not distinct in first 31 characters
 * - 'Non-distinct Identifiers: External Names' warning issued for both  C90 and C99 */
extern int abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz1;     
extern int abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz2;

Relevant Configuration File Parameters

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

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