Resolving Function Pointer Type Warnings in ARMCC v5 to CLANG v6 Transition

A practical guide to resolve function pointer type warnings when transitioning from ARMCC v5 to CLANG v6 in C programming.
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Navigating Compiler Changes: From ARMCC v5 to CLANG v6

Transitioning between different versions of compilers can come with its own set of challenges. If you've recently moved from ARMCC v5 to CLANG v6, you may have encountered warning messages that impede your progress. This guide will explore a specific situation involving function pointers and how to resolve the associated warning messages you may face.

The Problem: Function Pointer Warnings

When moving to CLANG v6, a warning message appears that reads:

[[See Video to Reveal this Text or Code Snippet]]

Essentially, this warning indicates that the function pointer types you're trying to use are incompatible—this is likely due to differences in how types are defined between the two compiler versions. To help clarify, let's break down the code that leads to this problem.

Existing Code Structure

You might have code structured like this:

[[See Video to Reveal this Text or Code Snippet]]

You might then call the initialization like this:

[[See Video to Reveal this Text or Code Snippet]]

The warning indicates that CLANG v6 interprets the function pointers differently from ARMCC v5, leading to the incompatible function pointer types.

Solution: Consistent Structure Definitions

The path to resolution lies in ensuring that the structure types and their definitions are compatible across the different compiler versions. Specifically, here are the steps to resolve the issue:

1. Define Your Struct Properly

Make sure that the structure is defined consistently before using it in your callback or elsewhere in your code. The fix was as simple as defining the structure like this:

[[See Video to Reveal this Text or Code Snippet]]

2. Update your Callback Function

Ensure the callback function matches the expected type as defined in your typedef:

[[See Video to Reveal this Text or Code Snippet]]

3. Adjust Initialization Call

With the structure defined properly, the initialization should work without warnings:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

By making your type definitions clear and ensuring your function pointers match expected types, you can resolve the warning when switching from ARMCC v5 to CLANG v6. It’s always a good practice to review type definitions and ensure consistency when transitioning between different compilers to maintain code integrity and prevent issues like these.

Keep coding and enjoy the enhanced capabilities of CLANG v6! If you encounter other challenges during this transition, feel free to share your questions for further assistance.