This function returns 1 if the markup identified by oid and pos can be deleted without context errors. It returns 0 if context errors would result if the markup was deleted.

All markup except included marked sections can be identified solely by oid. Both oid and pos must be given to specify an included marked section.

If oid is omitted, then oid_caret is used.

If content is given and non-zero, then this function returns 1 when no context errors would occur if both the markup and its content are deleted.

When testing whether markup can be deleted without context errors, this function will not do context transformations (such as tag substitutions, insert around to fix, insert required tags, remove redundant tags, and so on).