How do I suppress PC-Lint errors for C99-style initialization of structure members?

Question

I am using PC-Lint 8.00x with the following options:

+v -wlib(1) +fan +fas

I receive a number of error messages from PC-Lint when I run code similar to the following:

typedef union
{
    struct
    {
        unsigned int a : 4;
        unsigned int b : 4;
        unsigned int c : 4;
        unsigned int d : 4;
    } bits;
    unsigned short value;
} My_Value;

int main (void)
{
    My_Value test[] =
    {
        {
            .bits.a = 2,
            .bits.b = 3,    //Errors 133 and 10
            .bits.c = 2,
            .bits.d = 3,
        },
        {
            .bits.a = 1,
            .bits.b = 1,    //Errors 133 and 10
            .bits.c = 1,
            .bits.d = 0,
        },
    };

    /* Do something meaningful. */

    return 0;
}

The reported errors are defined by PC-Lint as follows:

Error 133: Too many initializers for aggregate 'unknown-name'

Error 10: Expecting '}'

I have tried searching Gimpel and have done some Google searches, but I cannot find anything useful. The code functions as intended and everything initializes properly. Here are my questions.

1. Does PC-Lint 8.00x support C99 style initialization of structure members?

2. If so, what options/flags do I have to set for PC-Lint to suppress these messages globally?

EDIT
I should have been more detailed in regards to question 2. I would like to globally suppress these messages in regards to my usage of designated initializers as shown above. I cannot suppress them globally for all situations as these errors can detect true errors in the code.

I don't know if nesting the member fields like that (e.g. `.bits.a`) is really okay. I would suspect you need to do e.g. `My_value test[] = { { { .a = 2, .b = 3, .c = 2, .d = 3 } }, ... }`. — Some programmer dude, Apr 02 '14 at 21:23
@JoachimPileborg That's a good point. I have seen some examples of using a designated initializer list to initialize nested structs (like [this](http://http://publib.boulder.ibm.com/infocenter/lnxpcomp/v8v101/index.jsp?topic=%2Fcom.ibm.xlcpp8l.doc%2Flanguage%2Fref%2Fdesignators.htm)), but I do not know for certain if this is proper C99. I may need to open another question... — embedded_guy, Apr 02 '14 at 22:01
It appears that my usage of a designated initializer list as written above is valid. However, I still can't get PC-Lint to play nice with this particular implementation. — embedded_guy, Apr 10 '14 at 23:59
I agree that it's valid; the grammar permits a *designator-list*, and `.bits.a` qualifies (and gcc and clang both accept it). But what happens if you move the `.bits` up a level? — Keith Thompson, Jul 09 '14 at 23:12
@KeithThompson, It looks like you are onto something. If I change to `[0].bits.a = 1` and continue through `[1].bits.d = 0` PC-Lint doesn't complain anymore and armcc still compiles it correctly. That may be my best option. — embedded_guy, Jul 09 '14 at 23:53

Simeon Pilgrim · Answer 1 · 2014-07-09T22:11:40.940

2

Not sure to the C99 and 8.00x support question, as I have 9.00k installed. But 9.00k dislikes your form of union initialization, but Visual Studio has no issue.

But for Jacchim Pileborg's case it just emits a Info 708: union initialization while might be safer to turn off.

As noted in the comments you dont want to fully globally remove these error types, so -e133 and -e10 will not solve your problems.

So using Joachim's form, I can using a macro suppress it like so:

typedef union
{
    struct
    {
        unsigned int a : 4;
        unsigned int b : 4;
        unsigned int c : 4;
        unsigned int d : 4;
    } bits;
    unsigned short value;
} My_Value;

#define MY_UNION(A,B,C,D) /*lint -save -e708*/{{.a=(A),.b=(B),.c=(C),.d=(D)}}/*lint -restore*/

int main(void)
{
    My_Value test[] =
    {
        MY_UNION(2, 3, 2, 1),
        MY_UNION(1, 2, 3, 4)
    };

    return 0;
}

Ugly, but as you have nothing to make the lint commands to stick to as it's all anonymous, you ether have to put inline commands explicitly or via a macro.

edited Jul 09 '14 at 22:11

answered Jul 09 '14 at 02:19

Simeon Pilgrim

22,906
3
32
45

Thanks, Simeon. I suppose I should have been more detailed about question number 2. I would like to suppress those messages globally as they apply to this particular situation. However, both of those errors can be potentially useful so I do not want them disabled for all situations. That's interesting that 9.00k does not like @JoachimPileBorg and my initializations... Either one of which should work under C99. +1 – embedded_guy Jul 09 '14 at 15:20
@embedded_guy 9.00k does not complain about this as bad, but it does have an `info 708` which would be safer to supress, or suppress file by file. The real issue is that what your doing is not really a class of thing (other than the 708 union initialization) thus you cannot suppress this instance everywhere. Now you could put into a MACRO then suppress those errors for that symbol. – Simeon Pilgrim Jul 09 '14 at 21:51
The macro option is worth considering. Although my manager has decided that it is unacceptable to have *any* lint comments in the code base, hence the desire to suppress globally. However, I may be able to get around that by adding `-emacro(708, MY_UNION)` to my `options.lnt` file. – embedded_guy Jul 10 '14 at 00:03

Keith Thompson · Accepted Answer · 2014-07-11T21:21:17.267

As far as I can tell, this syntax:

My_Value test[] =
{
    {
        .bits.a = 2,
        .bits.b = 3,
        .bits.c = 2,
        .bits.d = 3,
    },
    {
        .bits.a = 1,
        .bits.b = 1,
        .bits.c = 1,
        .bits.d = 0,
    },
};

is valid in C99 (and C11). Looking in section 6.7.8 of the standard, the thing preceding the = in an initializer is a designator-list, which is a sequence of one or more designators. .bits.a is valid in that context.

Apparently PC-Lint doesn't support that syntax. (You might want to notify the maintainers, unless it's already supported in a later version.)

As a workaround, if you change it to this:

My_Value test[] =
{   
    { .bits =
        {   
            .a = 2,
            .b = 3,
            .c = 2,
            .d = 3,
        },
    },
    { .bits =
        {   
            .a = 1,
            .b = 1,
            .c = 1,
            .d = 0,
        },
    },
};

it's still valid C (and arguably clearer) and, based on what you just wrote in a comment, PC-Lint accepts it.

(If you want to be even more explicit, you might consider adding [0] = and [1] = designators.)

UPDATE : QUoting a new commment:

The good people at Gimpel software have responded stating that "this appears to be a bug" and are working to correct it.

PC-Lint 9.00k has no issues with the second form posted above. I'd go with this. — Simeon Pilgrim, Jul 10 '14 at 00:08
Spot on, I just verified with 8.00x and PC-Lint is happy and it still conveys the original intention of the code. Thanks, Keith and thanks @SimeonPilgrim for breathing new life into a question that I thought would remain unanswered. — embedded_guy, Jul 10 '14 at 00:10
@SimeonPilgrim and Keith, The good people at Gimpel software have responded stating that "this appears to be a bug" and are working to correct it. Thanks again! — embedded_guy, Jul 11 '14 at 21:19

How do I suppress PC-Lint errors for C99-style initialization of structure members?

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