<![CDATA[MISRA Discussion Forums - 6.5 Identifiers]]> https://forum.misra.org.uk/ Thu, 05 Nov 2026 15:12:57 +0000 MyBB <![CDATA[Rule 5.2 : confusion]]> https://forum.misra.org.uk/showthread.php?tid=1402 Thu, 01 Mar 2018 16:08:43 +0000 ankitshah413]]> https://forum.misra.org.uk/showthread.php?tid=1402
I am getting MISRA 5.2 rule violation in my project. The code for which i am getting violation is a structure that is declared as extern in one header file. The code example is as under

1.h
Code:
extern struct con tmp_ev;

2.c
Code:
struct con tmp_ev;
cioF_get(&tmp_ev);

3.c
Code:
struct con tmp_ev;
(void)eeF_read(CON, &tmp_ev);

I get the warning only in 2.c in the line struct con tmp_ev; saying that declaration of symbol tmp_ev hides symbol tmp_ev and not in 3.c . Both 2.c and 3.c include the 1.h header file.

I am confused why this issue is present. Can anyone help me resolve this issue?

Thank you]]>
I am getting MISRA 5.2 rule violation in my project. The code for which i am getting violation is a structure that is declared as extern in one header file. The code example is as under

1.h
Code:
extern struct con tmp_ev;

2.c
Code:
struct con tmp_ev;
cioF_get(&tmp_ev);

3.c
Code:
struct con tmp_ev;
(void)eeF_read(CON, &tmp_ev);

I get the warning only in 2.c in the line struct con tmp_ev; saying that declaration of symbol tmp_ev hides symbol tmp_ev and not in 3.c . Both 2.c and 3.c include the 1.h header file.

I am confused why this issue is present. Can anyone help me resolve this issue?

Thank you]]> <![CDATA[MISRA C 2004 rule 5.2 vioated on pointer as argument]]> https://forum.misra.org.uk/showthread.php?tid=1061 Thu, 05 Jun 2014 16:32:47 +0000 Newmerlin]]> https://forum.misra.org.uk/showthread.php?tid=1061
Rule 5.2 deals with identifiers declared with block scope that hide identifiers declared at an outer block, or file, scope. It does not apply to identifiers declared in other translation units.

extern void SerialMaster_task(void *p_arg);

Warning[Pm017]: symbol hides parameter "p_arg" (declared at line 380) - identifiers in an inner scope shall not use the same name as an identifier in an outer scope, and therefore hide the identifier (MISRA C 2004 rule 5.2)

A parameter in the *declaration* of an external subroutine does not define a symbol in the current context.

---
Can you elaborate about why the source line above invokes MISRA C 2004 rule 5.2?

Dave Bailey
IAR Systems]]>
Rule 5.2 deals with identifiers declared with block scope that hide identifiers declared at an outer block, or file, scope. It does not apply to identifiers declared in other translation units.

extern void SerialMaster_task(void *p_arg);

Warning[Pm017]: symbol hides parameter "p_arg" (declared at line 380) - identifiers in an inner scope shall not use the same name as an identifier in an outer scope, and therefore hide the identifier (MISRA C 2004 rule 5.2)

A parameter in the *declaration* of an external subroutine does not define a symbol in the current context.

---
Can you elaborate about why the source line above invokes MISRA C 2004 rule 5.2?

Dave Bailey
IAR Systems]]> <![CDATA[Rule #5.1 clarification]]> https://forum.misra.org.uk/showthread.php?tid=926 Mon, 10 Dec 2012 15:49:20 +0000 gs]]> https://forum.misra.org.uk/showthread.php?tid=926 The conversation at http://www.misra.org.uk/forum/viewtopic.php?f=61&t=508 states identifiers longer than 31 characters are permitted. However, the exemplar suite suggest such identifiers are, per se, prohibited. Which is correct?]]> The conversation at http://www.misra.org.uk/forum/viewtopic.php?f=61&t=508 states identifiers longer than 31 characters are permitted. However, the exemplar suite suggest such identifiers are, per se, prohibited. Which is correct?]]> <![CDATA[Rule 5.5 and local static variables]]> https://forum.misra.org.uk/showthread.php?tid=865 Wed, 16 Nov 2011 12:43:42 +0000 pkruk]]> https://forum.misra.org.uk/showthread.php?tid=865
I wanted to confirm if having local static variables with the same name in different functions is not compliant with rule 5.5.
For example:

Code:
void foo1() {
    static int x1 = 0; /* Not compliant - foo1, foo2 */
    static int x2 = 0; /* Not compliant - foo1, foo2 */
}
void foo2() {
    static int x1 = 0; /* Not compilant - foo1, foo2 */
    int x2;            /* Not compliant - foo1, foo2 */
    int x3;            /* Not compliant - global, foo2 */
}
extern int x3; /* Not compliant - global, foo2 */

This is similar to http://www.misra-c.com/forum/viewtopic.php?f=61&t=812 and http://www.misra-c.com/forum/viewtopic.p...=962#p1807 but I just wanted a clear confirmation.

Thanks]]>
I wanted to confirm if having local static variables with the same name in different functions is not compliant with rule 5.5.
For example:

Code:
void foo1() {
    static int x1 = 0; /* Not compliant - foo1, foo2 */
    static int x2 = 0; /* Not compliant - foo1, foo2 */
}
void foo2() {
    static int x1 = 0; /* Not compilant - foo1, foo2 */
    int x2;            /* Not compliant - foo1, foo2 */
    int x3;            /* Not compliant - global, foo2 */
}
extern int x3; /* Not compliant - global, foo2 */

This is similar to http://www.misra-c.com/forum/viewtopic.php?f=61&t=812 and http://www.misra-c.com/forum/viewtopic.p...=962#p1807 but I just wanted a clear confirmation.

Thanks]]> <![CDATA[Rule 5.2, at what scope is the rule broken?]]> https://forum.misra.org.uk/showthread.php?tid=796 Mon, 06 Dec 2010 14:33:19 +0000 joa07]]> https://forum.misra.org.uk/showthread.php?tid=796
Rule 5.2 says that an identifier in a inner scope shall not hide an identifier in an outer scope.
I have two cases where I'm not sure what the rule says.

1. May a function use the name of an identifier that is local for this translation unit, but may be extern global for another translation unit? The first translation unit does not know this identifier at compile-time, so this error should only be detectable at link-time.

2. If the first question was a Yes, does this following code break this rule (it may brake some other Misra rules)?
Code:
int func1(void) {
    int var = 23;
    return var;
}

extern double var;    /* The name is reused here, global scope. Probably breaks rule 8.8 */

double func2(void) {
    return var;
}
]]>
Rule 5.2 says that an identifier in a inner scope shall not hide an identifier in an outer scope.
I have two cases where I'm not sure what the rule says.

1. May a function use the name of an identifier that is local for this translation unit, but may be extern global for another translation unit? The first translation unit does not know this identifier at compile-time, so this error should only be detectable at link-time.

2. If the first question was a Yes, does this following code break this rule (it may brake some other Misra rules)?
Code:
int func1(void) {
    int var = 23;
    return var;
}

extern double var;    /* The name is reused here, global scope. Probably breaks rule 8.8 */

double func2(void) {
    return var;
}
]]> <![CDATA[Rule 5.5 and unused extern declarations]]> https://forum.misra.org.uk/showthread.php?tid=661 Wed, 03 Jun 2009 12:30:24 +0000 roberto]]> https://forum.misra.org.uk/showthread.php?tid=661
Code:
extern int a;
extern int f(int x);
but never defines or references that externally-declared identifiers.
Suppose also that the whole program is constituted by f.c and g.c, where g.c contains
Code:
static int a = 3;
static int f(int x) {
  return x+a;
}
Note that there are no other files in the program and that the program is valid C.
In particular, no compilation unit defines or uses the identifiers declared in f.c.

Is this code violating rule 5.5?
Thanks,

Roberto]]>
Code:
extern int a;
extern int f(int x);
but never defines or references that externally-declared identifiers.
Suppose also that the whole program is constituted by f.c and g.c, where g.c contains
Code:
static int a = 3;
static int f(int x) {
  return x+a;
}
Note that there are no other files in the program and that the program is valid C.
In particular, no compilation unit defines or uses the identifiers declared in f.c.

Is this code violating rule 5.5?
Thanks,

Roberto]]> <![CDATA[A signed bit field of 1 bit length is not useful]]> https://forum.misra.org.uk/showthread.php?tid=622 Sun, 08 Feb 2009 08:41:45 +0000 JonM]]> https://forum.misra.org.uk/showthread.php?tid=622
How about - following the same outline structure of the following rule 7.1, something like:

A signed bit field of 1 bit length is treated as ...

There is a danger of ...

They are problematic when ...

It is better not to use signed bit fields of 1 bit length use ...

Jonathan]]>
How about - following the same outline structure of the following rule 7.1, something like:

A signed bit field of 1 bit length is treated as ...

There is a danger of ...

They are problematic when ...

It is better not to use signed bit fields of 1 bit length use ...

Jonathan]]> <![CDATA[Does 5.6 or 5.7 apply to block scope identifiers?]]> https://forum.misra.org.uk/showthread.php?tid=518 Thu, 15 May 2008 15:30:53 +0000 gs]]> https://forum.misra.org.uk/showthread.php?tid=518
Quote:No identifier name should be reused.

Regardless of scope, no identifier should be re-used across any files in the system. This rule incorporates the provisions of Rules 5.2, 5.3, 5.4, 5.5 and 5.6.

Does this advisory apply to block scope variables? The accompanying text says the rule incorporates the provisions of the other rules, but does not say if the rule is limited to just those provisions.

Rule 5.7 appears to constitute a stricter version of rule 5.6, which raises the question, "Does 5.6 apply to block scope variables?" as well.]]>
Quote:No identifier name should be reused.

Regardless of scope, no identifier should be re-used across any files in the system. This rule incorporates the provisions of Rules 5.2, 5.3, 5.4, 5.5 and 5.6.

Does this advisory apply to block scope variables? The accompanying text says the rule incorporates the provisions of the other rules, but does not say if the rule is limited to just those provisions.

Rule 5.7 appears to constitute a stricter version of rule 5.6, which raises the question, "Does 5.6 apply to block scope variables?" as well.]]> <![CDATA[Rule 5.6 / Rule 5.7]]> https://forum.misra.org.uk/showthread.php?tid=289 Thu, 20 Jul 2006 15:48:40 +0000 sparker]]> https://forum.misra.org.uk/showthread.php?tid=289
Is the intention that one deviates from R5.7 leaving R5.6 to catch the most important cases? If so that isn't very clear from the text.

(Overall I'd be surprised if anyone ever sticks to R5.7 since it means that every identifier in your program, even every local, has to differ from every other. That means no \"i\", \"j\", \"p\", \"speed\", \"rpm\", ..., \"index\", etc.)]]>
Is the intention that one deviates from R5.7 leaving R5.6 to catch the most important cases? If so that isn't very clear from the text.

(Overall I'd be surprised if anyone ever sticks to R5.7 since it means that every identifier in your program, even every local, has to differ from every other. That means no \"i\", \"j\", \"p\", \"speed\", \"rpm\", ..., \"index\", etc.)]]> <![CDATA[Rule 5.1]]> https://forum.misra.org.uk/showthread.php?tid=239 Wed, 05 Apr 2006 22:37:19 +0000 quangp]]> https://forum.misra.org.uk/showthread.php?tid=239
Does this rule disallow to use identifier that has more than 31 characters? Even though the first 31 characters are guaranteed to be distinct.

Thanks,

quangp]]>
Does this rule disallow to use identifier that has more than 31 characters? Even though the first 31 characters are guaranteed to be distinct.

Thanks,

quangp]]>