doc: OPENSSL_CORE_CTX should never be cast to OSSL_LIB_CTX
@@ -220,10 +220,14 @@ the thread that is stopping and gets passed the provider context as an
argument. This may be useful to perform thread specific clean up such as
freeing thread local variables.
-core_get_libctx() retrieves the library context in which the library
+core_get_libctx() retrieves the core context in which the library
object for the current provider is stored, accessible through the I<handle>.
-This may sometimes be useful if the provider wishes to store a
-reference to its context in the same library context.
+This function is useful only for built-in providers such as the default
+provider. Never cast this to OSSL_LIB_CTX in a provider that is not
+built-in as the OSSL_LIB_CTX of the library loading the provider might be
+a completely different structure than the OSSL_LIB_CTX of the library the
+provider is linked to. Use L<OSSL_LIB_CTX_new_child(3)> instead to obtain
+a proper library context that is linked to the application library context.
core_new_error(), core_set_error_debug() and core_vset_error() are
building blocks for reporting an error back to the core, with
