QA C Help - Rule 8.8

		MISRA-C:2004 Rule 8.8: (Required)			An external object or function shall be declared in one and only one file.

Normally this will mean declaring an external identifier in a header file, that will be included in any file where the identifier is defined or used. For example:

extern int16_t a;

in featureX.h, then to define a:

#include <featureX.h>
int16_t a = 0;

There may be one or there may be many header files in a project, but each external object or function shall only be declared in one header file.

QAC messages that encompass this guideline:

1513 Identifier '%1s' with external linkage has separate non-defining declarations in more than one location.

3222 Object with external linkage declared at block scope.

3408 '%s' has external linkage and is being defined without any previous declaration.

3447 '%s' is being declared with external linkage but this declaration is not in a header file.

3451 The global identifier '%s' has been declared in more than one file.

(c) The Motor Industry Research Association, 2004

QA C Source Code Analyser 8.1.2
MISRA-C:2004 Compliance Module 3.2
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1513	Identifier '%1s' with external linkage has separate non-defining declarations in more than one location.
3222	Object with external linkage declared at block scope.
3408	'%s' has external linkage and is being defined without any previous declaration.
3447	'%s' is being declared with external linkage but this declaration is not in a header file.
3451	The global identifier '%s' has been declared in more than one file.