Are char* and signed char* compatible (SCM_BYTEVECTOR_CONTENTS)?

[Vivien Kraus]

Hello,

I’m trying to use a bytevector from C.

1. According to an example in the manual, SCM_BYTEVECTOR_CONTENTS can
be assigned to a char*.

2. Also from the manual, it is a signed char*.

3. I've found this question online saying they are not compatible (
https://stackoverflow.com/questions/12769500/why-is-char-not-compatible-with-signed-char-or-unsigned-char
).

As I understand it, at least one of the above 3 affirmations is
incorrect. Could someone clarify this to me?