Better document side-effect free and pure C functions

* doc/lispref/internals.texi (Writing Emacs Primitives):
Document that side-effect free and pure properties of C functions
are defined in byte-opt.el.

(cherry picked from commit 4726900fdc5b0736feb03e928594eb64262f9bd5)

diff --git a/doc/lispref/internals.texi b/doc/lispref/internals.texi
index ff09e0aca1cccd3d54ae24413b5d1d73a470a9b3..c6ca8159313e12a0780b4758fc58d1281959511f 100644 (file)
--- a/doc/lispref/internals.texi
+++ b/doc/lispref/internals.texi
@@ -1164,7 +1164,8 @@ functions.
 
   If you define a function which is side-effect free or pure, give it
 a non-@code{nil} @code{side-effect-free} or @code{pure} property,
-respectively (@pxref{Standard Properties}).
+respectively (@pxref{Standard Properties}).  See the lists defined in
+@samp{byte-opt.el}.
 
 @node Writing Dynamic Modules
 @section Writing Dynamically-Loaded Modules