(String Conversion) <string-to-number>: Document

that a float is returned for integers that are too large.

1 files changed, 3 insertions, 1 deletions

diff --git a/lispref/strings.texi b/lispref/strings.texi
index b80dc244ee0..f35f94b2bc4 100644
--- a/lispref/strings.texi
+++ b/lispref/strings.texi
@@ -536,7 +536,9 @@ This function returns the numeric value of the characters in
 in that base.  If @var{base} is @code{nil}, then base ten is used.
 Floating point conversion always uses base ten; we have not implemented
 other radices for floating point numbers, because that would be much
-more work and does not seem useful.
+more work and does not seem useful.  If @var{string} looks like an
+integer but its value is too large to fit into a Lisp integer,
+@code{string-to-number} returns a floating point result.
 
 The parsing skips spaces and tabs at the beginning of @var{string}, then
 reads as much of @var{string} as it can interpret as a number.  (On some