Enhance enif_has_pending_exception

Sverker Eriksson came up with the following idea: to handle a future
ability for NIFs to raise more than just badarg exceptions, modify the
recently-added enif_has_pending_exception function to take a second
argument: a pointer to ERL_NIF_TERM. If this argument is a null
pointer, ignore it. Otherwise, if the first argument, an ErlNifEnv*,
has an associated exception, set the pointed-to ERL_NIF_TERM of the
second argument to the value of the exception term. Add new tests and
documentation for this modification.

1 files changed, 9 insertions, 3 deletions

diff --git a/erts/doc/src/erl_nif.xml b/erts/doc/src/erl_nif.xml
index 4bad8b253c..155aee2f42 100644
--- a/erts/doc/src/erl_nif.xml
+++ b/erts/doc/src/erl_nif.xml
@@ -778,11 +778,17 @@ typedef enum {
       and return true, or return false if <c>term</c> is not an unsigned integer or is
       outside the bounds of type <c>unsigned long</c>.</p></desc>
     </func>
-    <func><name><ret>int</ret><nametext>enif_has_pending_exception(ErlNifEnv* env)</nametext></name>
+    <func><name><ret>int</ret><nametext>enif_has_pending_exception(ErlNifEnv* env, ERL_NIF_TERM* reason)</nametext></name>
       <fsummary>Check if an exception has been raised.</fsummary>
       <desc><p>Return true if a pending exception is associated
-      with the environment <c>env</c>. The only possible exception is currently
-      <c>badarg</c> (see <seealso marker="#enif_make_badarg">enif_make_badarg</seealso>).</p></desc>
+      with the environment <c>env</c>. If <c>reason</c> is a null pointer, ignore it.
+      Otherwise, if there's a pending exception associated with <c>env</c>, set the ERL_NIF_TERM
+      to which <c>reason</c> points to the value of the exception's term. For example, if
+      <seealso marker="#enif_make_badarg">enif_make_badarg</seealso> is called to set a
+      pending <c>badarg</c> exception, a subsequent call to <c>enif_has_pending_exception(env, &amp;reason)</c>
+      will set <c>reason</c> to the atom <c>badarg</c>, then return true.</p>
+      <p>See also: <seealso marker="#enif_make_badarg">enif_make_badarg</seealso>.</p>
+      </desc>
     </func>
     <func><name><ret>int</ret><nametext>enif_inspect_binary(ErlNifEnv* env, ERL_NIF_TERM bin_term, ErlNifBinary* bin)</nametext></name>
       <fsummary>Inspect the content of a binary</fsummary>