Bug in app_error_weak.h: Function should not be declared weak in global include file!

[puz_md]

Hi, I found a bug with weak function declarations in SDK11, using GCC.

app_error_weak.h contains the following declaration:

#ifdef __CC_ARM
    void app_error_fault_handler(uint32_t id, uint32_t pc, uint32_t info);
#else
    __WEAK void app_error_fault_handler(uint32_t id, uint32_t pc, uint32_t info);
#endif

app_error_weak.h is included in app_error.h and so indirectly in multiple header files.

This leads to a situation where I cannot define "strong" implementations of app_error_fault_handler() in files where I use specific other include files (it is not clear which include files I may use and which not). For example, if I include softdevice_handler.h in main.c, I cannot define a "strong" app_error_fault_handler() in main.c at the same time, because the function will be declared as weak due to indirect inclusion of app_error_weak.h

In short, I will get two weak implementations of app_error_fault_handler(), one defined in main.c and one defined in app_error_weak.c. GCC will pick one of these functions randomly and discard the other implementation.

Proposed solutions:

(1) Do not declare the function as weak in app_error_weak.h. It should be sufficient to use the weak attribute in app_error_weak.c where it is defined.

(2) Do not include app_error_weak.h in app_error.h, and use a non-weak declaration of the function in app_error.h. app_error_weak.h seems to becomes obsolete in this case.

For a clean implementation, I would prefer (2).

[puz_md]

Yes, it's exactly the same issue. And I agree with astewart. Include files are treated like part of the .c file (they are copied into the .c file by the preprocessor), and if a function is declared separately before it is defined, the declaration attributes are adopted to the definition part. This is a C specific feature, not GCC specific.