SEGGER Embedded Studio v6.20 compiler warning

[Casper Kronborg Pedersen]

Hi DevZone,

I recently updated my version of SEGGER Embedded Studio for ARM to v6.20. Now, warnings that were not shown before are caught.

I want to ignore the warning triggered specifically when giving reference to a member of a packed struct I am getting the following warning:

<taking address of packed member of 'struct <anonymous>' may result in an unaligned pointer value [-Waddress-of-packed-member]>

 

Example:

typedef struct __attribute__((__packed__))
{
    uint16_t a;                   
    uint16_t b;                   
} ExampleStruct;

void ExampleFunction(uint16_t* var)
{
    // Place data at given pointer address
}

int main(void)
{
    ExampleStruct exampleStruct;

    ExampleFunction(&exampleStruct.a);
    ExampleFunction(&exampleStruct.b);

    return 0;
}

Is it possible to omit certain compiler warnings, or to specify to the compiler that I am doing this intentionally?

[Einar Thorsrud]

Hi,

I am not aware of any way to suppress specific warnings in Segger Embedded Studio (with a few specific exceptions as documented in Embedded Studio Code Options). You could ask SEGGER directly, though.

[Casper Kronborg Pedersen]

Hi Einar,

Sorry for asking Nordic about this. To be honest I sometimes forget that you and SEGGER are not a single unit.

I will post a Ticket to SEGGER directly, thank you for the link.

However, if it is ok with you then I could post the answer here if there is one. But I guess that would require this post to stay open until it is resolved?

[Einar Thorsrud]

Hi,

Yes, if you get this resolved with the help from Segger it would be great if you post the solution here. Just keep it open

[Casper Kronborg Pedersen]

Ok, I have just sent a ticket. Fingers crossed.

Br. Casper

[Casper Kronborg Pedersen]

Word is back from SEGGER.

Apparently, when using a Nordic license for SEGGER, one has to use the community forums and not the direct support.

https://forum.segger.com/

However, I still got a pointer in the right direction from the Engineer who got back to me and was able to figure it out.

Solution:

1. Go to Project Options -> Code -> Compiler -> Additional C/C++ Compiler Options
2. Make sure to chose  the "Common" build configuration if you want this for all build configurations. Alternatively select the specific build configuration of interest.
3. Add the line -Wno-address-of-packed-member
4. Save and rebuild

Also, check out https://gcc.gnu.org/onlinedocs/gcc/Option-Summary.html for more options.

Hope this helps someone. 

Br. Casper