_REENT_CHECK_VERIFY calls __assert_func even if NDEBUG is defined

[R. Diez]

> An alternative change would require modifications to all the
> existing conversion routines using eBalloc() and their callers
> to do checking of return values and bubble up to the user,
> setting errno to ENOMEM.

I am not sure what conversion routines you are referring to. I found this issue with rand(), because lwIP needs a source of random numbers. It is normally not expected that rand() calls malloc(). rand() returns no error indication, according to the POSIX standard:

https://pubs.opengroup.org/onlinepubs/9699919799/functions/rand.html

So using errno here is difficult.

rand() ends up calling _REENT_CHECK, which does a malloc(). What do you mean with eBalloc()?

  
> The memory in question is being allocated by Balloc()
> which is part of the mprec.c solution used in newlib.
> The allocated _REENT_MP_FREELIST has an array
> of storage to reuse for different k values so newlib will reuse
> [...]

Does that apply in my scenario? I am building Newlib without thread support. There is no reent creation or destruction, as far as I can tell.

I have been digging further, and I believe (the code is not easy to follow) that these unexpected allocations come from using the "small reent". What does --enable-newlib-reent-small actually do? The README file at this location:

  https://sourceware.org/newlib/README

has this description:

  `--enable-newlib-reent-small'
    Enable small reentrant struct support.
    Disabled by default.

But it does not really say what the difference between the normal and "small" versions is.

Thanks in advance,
  rdiez