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, 4 insertions, 1 deletions

diff --git a/erts/emulator/beam/erl_nif.c b/erts/emulator/beam/erl_nif.c
index 7876785a76..36da6519f7 100644
--- a/erts/emulator/beam/erl_nif.c
+++ b/erts/emulator/beam/erl_nif.c
@@ -741,8 +741,11 @@ Eterm enif_make_badarg(ErlNifEnv* env)
     BIF_ERROR(env->proc, BADARG);
 }
 
-int enif_has_pending_exception(ErlNifEnv* env)
+int enif_has_pending_exception(ErlNifEnv* env, ERL_NIF_TERM* reason)
 {
+    if (env->exception_thrown && reason != NULL) {
+	*reason = am_badarg;
+    }
     return env->exception_thrown;
 }