Fix compilation with -Wpedantic on GCC

[Mixaill]

Description

This PR does the following

• fixes empty declaration of 'enum' type does not redeclare tag error in the FreeRTOS_IPv4.h file.
• adds -Wpedantic to the GCC compilation flags
  • adds -Wno-pedantic for FreeRTOS_Sockets.c file in case you are using GCC to suppress warning

The main reason is that FreeRTOS_IPv4.h is a public header and in case an application uses -Wpedantic -Werror to compile, it will not be able to use FreeRTOS-Plus-TCP.

Checklist:

• I have tested my changes. No regression in existing tests.
• I have modified and/or added unit-tests to cover the code changes in this Pull Request.

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[moninom1]

Why is this needed, i see that by adding -Wpedantic to the GCC compilation flags only gives error in FreeRTOS_Sockets.c which you resolved above.

[Mixaill]

Reproduced in GCC 13.2

It looks like -std=gnu2x is also required to reproduce the error, but since it is a public header, this should be handled.

/opt/arm/gcc-13.2/bin/arm-none-eabi-gcc 

-mcpu=cortex-m7 -mfpu=fpv5-d16 -mfloat-abi=hard -mthumb -mlong-calls -mlittle-endian -Wall -Wextra -Werror -Wpedantic -Wno-psabi -fstack-usage -ffunction-sections -fdata-sections -fno-omit-frame-pointer -fvar-tracking -fvar-tracking-assignments -O0 -DDEBUG  -ggdb3 -gdwarf-5 -std=gnu2x -fdiagnostics-color=always -Wno-array-bounds -Wno-strict-aliasing -Wno-unused-but-set-variable

...
FreeRTOS_IPv4.h:46:10: error: empty declaration of 'enum' type does not redeclare tag [-Werror=pedantic]
   46 |     enum eFrameProcessingResult;

[moninom1]

Hi @Mixaill

Can you please help in updating on the above review comments.

[Mixaill]

@moninom1 Please take a look once again

Dismissing review as we do not want to add compiler specific stuff in the common source files

[aggarg]

Thank you for your contribution. I have the following suggestions:

• Warning from source/FreeRTOS_Sockets.c - We do not want to add compiler specific stuff in the common source files as those are built with multiple compilers. The recommended way to suppress the warning is to suppress it in the build system (preferably only for this file) if you enable pedantic option.

• Warning from source/include/FreeRTOS_IPv4.h - The correct way to address this warning is to remove the forward declaration of eFrameProcessingResult and move the following 2 function declarations to source/include/FreeRTOS_IPv4_Private.h:

  /* The function 'prvAllowIPPacket()' checks if a packets should be processed. */
  enum eFrameProcessingResult prvAllowIPPacketIPv4( const struct xIP_PACKET * const pxIPPacket,
                                                    const struct xNETWORK_BUFFER * const pxNetworkBuffer,
                                                    UBaseType_t uxHeaderLength );
  
  /* Check if the IP-header is carrying options. */
  enum eFrameProcessingResult prvCheckIP4HeaderOptions( struct xNETWORK_BUFFER * const pxNetworkBuffer );
  

  @tony-josi-aws has verified that these changes fix the warning - 129b4ce.

Would you like to make these changes or would you like us to?

[Mixaill]

@aggarg

• replaced changes in FreeRTOS_Sockets.c with -Wno-pedantic for this file
• replaced changes in FreeRTOS_IPv4.h with commits from @tony-josi-aws