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

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.

Answer 1

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.

Answer 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.