* data.c (Fstring_to_number): Document results if unparsable.

Fixes: debbugs:16551

2 files changed, 8 insertions, 3 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 4ed9ef9d2cf..4fa19d98f7f 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,8 @@
+2014-01-26  Paul Eggert  <eggert@cs.ucla.edu>
+
+        * data.c (Fstring_to_number): Document results if unparsable
+        (Bug#16551).
+
 2014-01-26  Jan Djärv  <jan.h.d@swipnet.se>
 
         * xterm.c (x_focus_changed): Check for non-X terminal-frame (Bug#16540)
diff --git a/src/data.c b/src/data.c
index 2a64c1bbf82..91a1d8b75fb 100644
--- a/src/data.c
+++ b/src/data.c
@@ -2523,12 +2523,12 @@ NUMBER may be an integer or a floating point number.  */)
 
 DEFUN ("string-to-number", Fstring_to_number, Sstring_to_number, 1, 2, 0,
        doc: /* Parse STRING as a decimal number and return the number.
-This parses both integers and floating point numbers.
-It ignores leading spaces and tabs, and all trailing chars.
+Ignore leading spaces and tabs, and all trailing chars.  Return 0 if
+STRING cannot be parsed as an integer or floating point number.
 
 If BASE, interpret STRING as a number in that base.  If BASE isn't
 present, base 10 is used.  BASE must be between 2 and 16 (inclusive).
-If the base used is not 10, STRING is always parsed as integer.  */)
+If the base used is not 10, STRING is always parsed as an integer.  */)
   (register Lisp_Object string, Lisp_Object base)
 {
   register char *p;