QA·C Help - 0779

	0779	[U] Identifier does not differ from other identifier(s) (e.g. '%s') within the specified number of significant characters.

Explicitly undefined		REFERENCE - ISO:C90-6.1.2 Identifiers - Implementation Limits

This identifier is not distinguishable from other identifiers in the same name space within the number of characters specified by the -NA option.

The -NA option should be configured to reflect (at least) the limitations of the implementation; but it may also be used to apply additional restriction. The -NA option specifies the number of characters to be considered significant in an identifier. This means that 2 identifiers within the same namespace and in the same scope must differ within this number of initial characters.

The ISO:C90 Standard Standard requires an implementation to support 31 character significance.
The ISO:C99 Standard Standard requires an implementation to support 63 character significance.

In practice, compilers may recognise even more. However, regardless of the capability of a particular implementation, it may be considered desirable to restrict the number of significant characters to a smaller number in order to improve readability.

Message 0779 is generated when identifiers cannot be distinguished within the number of characters specified by this option.

For example:


/*PRQA S 553,778,2017,3205,3207,3210,3408,3447 ++*/
/************************/
/* OPTIONS: -NA 10      */
/************************/

extern void foo(void)
{
    int a234567890x;                      /*      */
    int a234567890y;                      /* 0779 */

    int b234567890x;                      /*      */
    int b234567890X;                      /* 0779 */
}

MISRA C:2012 Rules applicable to message 0779:

Rule-1.3 (Required)	There shall be no occurrence of undefined or critical unspecified behaviour
Rule-5.2 (Required)	Identifiers declared in the same scope and name space shall be distinct