const: Add const keyword for all name pointer parameters

[MaJerle]

This pull requests fixes the compiler warning when creating TX objects with literal strings since we are passing literal string to the function accepting CHAR *, that can, by design, modify input parameter and therefore cause undefined system behavior.

All name pointers become const CHAR* type.

There is no backward incompatibility when creating objects, but there is a potential backward in-compatibility when calling tx_<modulename>_name_get function, because parameter shall be changed to const char* variable.

Currently we can get the name as:

CHAR* name;
tx_thread_name_get(..., &name);

New required function call:

const CHAR* name;
tx_thread_name_get(..., &name);

I've not seen tests for getting the name in the threadx, I also clearly assume that people using _get api are the minority.
From safety and quality standpoint, this upgrade makes a lot of sense.

PR checklist

• Updated function header with a short description and version number
• Added test case for bug fix or new feature
• Validated on real hardware C-M4, GCC

[fdesbiens]

@eclipse-threadx/iot-threadx-committers I need one of you to review this PR, please.

[fdesbiens]

Thank you for this contribution, @MaJerle. I asked the group of committers to review it. I appreciate your patience.

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[billlamiework]

In principle, I agree with this request, and we should have included this in the original APIs. However, now that the API has been public for 28 years, I would refrain from making this change. I don't like anything that alters the published API. That said, if we were to do this, we would also have to update the user guide and, I think, the name pointer storage in all the control blocks, e.g., TX_THREAD, TX_QUEUE, etc.

[MaJerle]

In principle, I agree with this request, and we should have included this in the original APIs. However, now that the API has been public for 28 years, I would refrain from making this change. I don't like anything that alters the published API. That said, if we were to do this, we would also have to update the user guide and, I think, the name pointer storage in all the control blocks, e.g., TX_THREAD, TX_QUEUE, etc.

I may sound nasty, but if it was not done correctly for 28 years, it doesn't mean it shouldn't be fixed now. The implementation can lead to bugs. There is zero backward incompatibility, nor realistically any docs need an update.

[gzzi]

I'm also interested by having const qualifier for name. I understand the point raised about API stability and certification.

@billlamiework would it be ok to use a #define in tx_user.h? I imagine something like:

// tx_user.h

#define TX_OBJECT_NAME_CONST

// tx_api.h

#ifdef TX_OBJECT_NAME_CONST
typedef const CHAR* TX_NAME_PTR;
#else
typedef CHAR* TX_NAME_PTR;
#endif

typedef struct TX_THREAD_STRUCT
{
...
    TX_NAME_PTR tx_thread_name;                /* Pointer to thread's name     */
...
} TX_THREAD;

UINT        _tx_thread_info_get(TX_THREAD *thread_ptr, TX_NAME_PTR* name, UINT *state, ULONG *run_count,
                UINT *priority, UINT *preemption_threshold, ULONG *time_slice,
                TX_THREAD **next_thread, TX_THREAD **next_suspended_thread);