| Issue |
171662
|
| Summary |
[clang-tidy] checker to get rid of raw function pointer usages
|
| Labels |
clang-tidy
|
| Assignees |
|
| Reporter |
denzor200
|
**Motivation**
Developers often write code like:
```
// BAD - Legacy C-style function pointer
void register_callback(void (*callback)(int, void*), void* user_data);
// BAD - Function taking raw function pointer
void process_data(int* array, size_t size, int (*transform)(int));
```
This approach is inflexible and cannot work with:
- Lambda expressions with captures;
- Function objects (functors);
- `std::bind` expressions;
- `std::mem_fn` expressions.
```
register_callback([&](int value) { /* lambda with capture */ }); // won't be compiled
process_data(arr, n, [](int x) { return x * 2; }); // won't be compiled
```
**Proposed Solution**
Add a clang-tidy check that identifies raw function pointer parameters and suggests converting them to more flexible alternatives:
```
// GOD - converted to std::function
void register_callback(std::function<void(int)> callback);
// GOD - converted to template version
template<typename F>
void process_data(int* array, size_t size, F&& transform);
```
Since the first option can negatively impact performance, it's better to use the second one whenever possible—in static functions and functions declared in A-files. However, the second option can lead to binary bloat, so it shouldn't be used for very large functions.
**Special Cases**
1. C API Compatibility
```
// Should NOT warn when extern "C" or __cdecl specified
extern "C" {
void take_c_api_callback(void (*callback)(int)); // No warning
}
```
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