diff options
| -rw-r--r-- | doc/lispref/sequences.texi | 5 | ||||
| -rw-r--r-- | src/fns.c | 4 |
2 files changed, 7 insertions, 2 deletions
diff --git a/doc/lispref/sequences.texi b/doc/lispref/sequences.texi index c7cf9f5e1af..5ae1567c128 100644 --- a/doc/lispref/sequences.texi +++ b/doc/lispref/sequences.texi @@ -155,7 +155,10 @@ This function generalizes @code{aref} (@pxref{Array Functions}) and @cindex copying sequences This function returns a copy of @var{seqr}, which should be either a sequence or a record. The copy is the same type of object as the -original, and it has the same elements in the same order. +original, and it has the same elements in the same order. However, if +@var{seqr} is empty, like a string or a vector of zero length, the +value returned by this function might not be a copy, but an empty +object of the same type and identical to @var{seqr}. Storing a new element into the copy does not affect the original @var{seqr}, and vice versa. However, the elements of the copy diff --git a/src/fns.c b/src/fns.c index 4524ff9b268..2311a6e041b 100644 --- a/src/fns.c +++ b/src/fns.c @@ -482,7 +482,9 @@ usage: (vconcat &rest SEQUENCES) */) DEFUN ("copy-sequence", Fcopy_sequence, Scopy_sequence, 1, 1, 0, doc: /* Return a copy of a list, vector, string, char-table or record. The elements of a list, vector or record are not copied; they are -shared with the original. */) +shared with the original. +If the original sequence is empty, this function may return +the same empty object instead of its copy. */) (Lisp_Object arg) { if (NILP (arg)) return arg; |