From: Taylor R Campbell <campbell@mumble.net>
Date: Sun, 30 Jun 2019 19:06:04 +0000 (+0000)
Subject: Document copysign.
X-Git-Tag: mit-scheme-pucked-10.1.12~7^2~33
X-Git-Url: https://birchwood-abbey.net/git?a=commitdiff_plain;h=ca82978311908c30227e1c5c2436bde49445a18a;p=mit-scheme.git

Document copysign.
---

diff --git a/doc/ref-manual/numbers.texi b/doc/ref-manual/numbers.texi
index 6cf04083c..1b592d274 100644
--- a/doc/ref-manual/numbers.texi
+++ b/doc/ref-manual/numbers.texi
@@ -1298,6 +1298,20 @@ inexact numbers are representable as exact numbers.
 The procedure @code{inexact->exact} has been deprecated by @urseven{}.
 @end deffn
 
+@deffn procedure copysign x1 x2
+Returns a real number with the magnitude of @var{x1} and the sign of
+@var{x2}.
+
+@example
+@group
+(copysign 123 -1)              @result{} -123
+(copysign 0. -1)               @result{} -0.
+(copysign -0. 0.)              @result{} 0.
+(copysign -nan.123 0.)         @result{} +nan.123
+@end group
+@end example
+@end deffn
+
 @node Numerical input and output, Fixnum and Flonum Operations, Numerical operations, Numbers
 @section Numerical input and output
 @cindex numerical input and output