False Positive MISRA 18.8

[Amir]

Hello,

I'm getting a false positive on rule 18.8. Here is what I'm seeing:

ealPcuComm.c:

#include "mcalUartApi.h"

void Eal_PcuCommManager(void)
{
    static PcuCommState_t pcuCommState = EAL_PCUCOMM_INIT;
    static uint32_t sendMsgCnt = 0;
    uint16_t rtn = 1;
    uint8_t sendMsg[DIFF_UART_MSG_SIZE] = {'\0'};
...
...

mcalUartApi.h:

#define DIFF_UART_MSG_SIZE (12U)

I'm getting a false positive on:
uint8_t sendMsg[DIFF_UART_MSG_SIZE] = {'\0'};

Error:
eal\ealPcuComm.c:53:10: style: Required. Variable-length array types shall not be used [misra-c2012-18.8]

[Daniel Marjamäki]

I spontaneosly wonder if you could have a preprocessing problem. If I copy/paste your code here I do not get this warning. If I comment out the define then the warning is shown. Does the warning go away if you replace DIFF_UART_MSG_SIZE with (12U) in your code?

[Amir]

Yes the warning does go away. But cppcheck doesn't use the preprocessor, correct? I can compile just find, my preprocessor is finding DIFF_UART_MSG_SIZE. But cppcheck doesn't seem to be finding it?

Here is misra.json:

{
    "script": "misra.py",
    "args": [
        "--rule-texts=../cppcheck/misra_rules.txt",
        "--suppress-rules 17.8"
    ]
}

Here is cppcheck command I'm using:
cppcheck -rp --inline-suppr --addon=..\cppcheck\misra.json ..\Sources -I ..\BCC

Regards,
Amir

[Daniel Marjamäki]

cppcheck preprocess the code. does it show some related warnings if you run: cppcheck --check-config ..\Sources -I..\BCC.

[Amir]

Hi Daniel,

Looks like cppcheck was not finding the header files. I've added the -I option for all the places to look for the .h files and it works now. Thanks for the help!

I'm curious, does the -I option search recursively through sub-directories?

Regards,
Amir

[Daniel Marjamäki]

I've added the -I option for all the places to look for the .h files and it works now.

Great!

I'm curious, does the -I option search recursively through sub-directories?

No. We have talked about such behavior. It would be convenient. Well the problem is if you include "foo.h" and there are both "path1/foo.h" and "path2/foo.h".

[Amir]

Good point, thanks for all the help, cppcheck has proven to be much easier to use than other paid options I've looked at for MISRA. Donation coming your way.

EDIT: How can I donate to your project?

[Daniel Marjamäki]

How can I donate to your project?

I believe the best options are either:
* You can sponsor cppcheck contributors. Me: http://github.com/danmar , not sure if anybody else has that option.
* You can sponsor future kickstarter projects. Do you want that I send you email when I create a Kickstarter project?