From b02f03c979cda37e43828cd6e1787649f1d8ca8c Mon Sep 17 00:00:00 2001 From: Steve Vinoski Date: Tue, 22 Feb 2011 18:07:57 -0500 Subject: add support for checking if an ERL_NIF_TERM is an exception Add the enif_is_exception function to allow callers to determine whether an ERL_NIF_TERM represents an exception. (Currently the only supported exception is badarg since only enif_make_badarg exists, but this will likely be expanded in future releases.) This allows NIF code to call other NIF functions that return ERL_NIF_TERM and properly check to see if the returned terms are exceptions. Without the enif_is_exception function, developers have to create their own means of checking whether a function creates an exception, such as returning boolean success/failure indicators or some other special value indicating that an exception is in effect. The declaration of enif_is_exception in erl_nif_api_funcs.h respects the order of declarations required to keep compatibility on Windows. Add a new test to verify the operation of enif_is_exception. Modify the erl_nif man page to add a description of enif_is_exception and also to clarify the requirements of calling the enif_make_badarg function. If code calls enif_make_badarg, the env passed in gets set with exception information and so the return value of the calling function MUST be the badarg term returned from enif_make_badarg. Also clarify that the result of enif_make_badarg may be passed only to enif_is_exception and not to any other NIF API functions. --- erts/emulator/beam/erl_nif.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'erts/emulator/beam/erl_nif.h') diff --git a/erts/emulator/beam/erl_nif.h b/erts/emulator/beam/erl_nif.h index 8050b3640a..d028567faf 100644 --- a/erts/emulator/beam/erl_nif.h +++ b/erts/emulator/beam/erl_nif.h @@ -31,9 +31,10 @@ ** 1.0: R13B04 ** 2.0: R14A ** 2.1: R14B02 "vm_variant" +** 2.2: R14B03 enif_is_exception */ #define ERL_NIF_MAJOR_VERSION 2 -#define ERL_NIF_MINOR_VERSION 1 +#define ERL_NIF_MINOR_VERSION 2 #include -- cgit v1.2.3