Clarification about the custom interface and macros.

* doc/mpfr.texi: added some text in Section "Custom Interface".
* src/mpfr.h: replaced the remaining FIXME by another comment.

git-svn-id: https://scm.gforge.inria.fr/anonscm/svn/mpfr/trunk@14462 280ebfd0-de03-0410-8827-d642c229c3f4

2 files changed, 9 insertions, 2 deletions

diff --git a/doc/mpfr.texi b/doc/mpfr.texi
index 424997714..2622b1c4b 100644
--- a/doc/mpfr.texi
+++ b/doc/mpfr.texi
@@ -3902,6 +3902,12 @@ to the application.
 Each function in this interface is also implemented as a macro for
 efficiency reasons: for example @code{mpfr_custom_init (s, p)}
 uses the macro, while @code{(mpfr_custom_init) (s, p)} uses the function.
+Note that the macro may evaluate arguments multiple times (or none).
+Moreover, macros implementing functions with the @code{void} return type
+may not be used in contexts where an expression is expected, e.g., inside
+@code{for(...)} or before a comma operator.
+@c These limitations with macros cannot be avoided in a C90 compatible way.
+@c In the future, inline functions could be used.
 
 Note 1: MPFR functions may still initialize temporary floating-point numbers
 using @code{mpfr_init} and similar functions. See Custom Allocation (GNU MP)@.
diff --git a/src/mpfr.h b/src/mpfr.h
index 2f4b8435c..1f2a01915 100644
--- a/src/mpfr.h
+++ b/src/mpfr.h
@@ -872,8 +872,9 @@ __MPFR_DECLSPEC int mpfr_total_order_p (mpfr_srcptr, mpfr_srcptr);
 /* In the implementation of these macros, we need to make sure that the
    arguments are evaluated one time exactly and that type conversion is
    done as it would be with a function. Tests should be added to ensure
-   that. */
-/* FIXME: the mpfr_custom_* macros are currently buggy. */
+   that.
+   Note that the macros for the custom interface are not concerned; the
+   MPFR manual has been clarified. */
 
 /* Prevent x from being used as an lvalue.
    Thanks to Wojtek Lerch and Tim Rentsch for the idea. */