diff options
Diffstat (limited to 'erts/doc/src/erl_nif.xml')
| -rw-r--r-- | erts/doc/src/erl_nif.xml | 81 |
1 files changed, 40 insertions, 41 deletions
diff --git a/erts/doc/src/erl_nif.xml b/erts/doc/src/erl_nif.xml index 3de94be9ff..4bad8b253c 100644 --- a/erts/doc/src/erl_nif.xml +++ b/erts/doc/src/erl_nif.xml @@ -66,34 +66,6 @@ </list> </warning> - <p>The NIF concept is officially supported from R14B. NIF source code - written for earlier experimental versions might need adaption to run on R14B - or later versions:</p> - <list> - <item>No incompatible changes between <em>R14B</em> and R14A.</item> - <item>Incompatible changes between <em>R14A</em> and R13B04: - <list> - <item>Environment argument removed for <c>enif_alloc</c>, - <c>enif_realloc</c>, <c>enif_free</c>, <c>enif_alloc_binary</c>, - <c>enif_realloc_binary</c>, <c>enif_release_binary</c>, - <c>enif_alloc_resource</c>, <c>enif_release_resource</c>, - <c>enif_is_identical</c> and <c>enif_compare</c>.</item> - <item>Character encoding argument added to <c>enif_get_atom</c> - and <c>enif_make_existing_atom</c>.</item> - <item>Module argument added to <c>enif_open_resource_type</c> - while changing name spaces of resource types from global to module local.</item> - </list> - </item> - <item>Incompatible changes between <em>R13B04</em> and R13B03: - <list> - <item>The function prototypes of the NIFs have changed to expect <c>argc</c> and <c>argv</c> - arguments. The arity of a NIF is by that no longer limited to 3.</item> - <item><c>enif_get_data</c> renamed as <c>enif_priv_data</c>.</item> - <item><c>enif_make_string</c> got a third argument for character encoding.</item> - </list> - </item> - </list> - <p>A minimal example of a NIF library can look like this:</p> <p/> <code type="none"> @@ -806,6 +778,12 @@ 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> + <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> + </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> <desc><p>Initialize the structure pointed to by <c>bin</c> with @@ -898,23 +876,37 @@ typedef enum { <func><name><ret>ERL_NIF_TERM</ret><nametext>enif_make_atom(ErlNifEnv* env, const char* name)</nametext></name> <fsummary>Create an atom term</fsummary> <desc><p>Create an atom term from the null-terminated C-string <c>name</c> - with iso-latin-1 encoding.</p></desc> + with iso-latin-1 encoding. If the length of <c>name</c> exceeds the maximum length + allowed for an atom (255 characters), <c>enif_make_atom</c> invokes + <seealso marker="#enif_make_badarg">enif_make_badarg</seealso>. + </p></desc> </func> <func><name><ret>ERL_NIF_TERM</ret><nametext>enif_make_atom_len(ErlNifEnv* env, const char* name, size_t len)</nametext></name> <fsummary>Create an atom term</fsummary> <desc><p>Create an atom term from the string <c>name</c> with length <c>len</c>. - Null-characters are treated as any other characters.</p></desc> + Null-characters are treated as any other characters. If <c>len</c> is greater than the maximum length + allowed for an atom (255 characters), <c>enif_make_atom</c> invokes + <seealso marker="#enif_make_badarg">enif_make_badarg</seealso>. + </p></desc> </func> <func><name><ret>ERL_NIF_TERM</ret><nametext>enif_make_badarg(ErlNifEnv* env)</nametext></name> <fsummary>Make a badarg exception.</fsummary> - <desc><p>Make a badarg exception to be returned from a NIF, and set - an associated exception reason in <c>env</c>. If - <c>enif_make_badarg</c> is called, the term it returns <em>must</em> - be returned from the function that called it. No other return value - is allowed. Also, the term returned from <c>enif_make_badarg</c> may - be passed only to - <seealso marker="#enif_is_exception">enif_is_exception</seealso> and - not to any other NIF API function.</p></desc> + <desc><p>Make a badarg exception to be returned from a NIF, and associate + it with the environment <c>env</c>. Once a NIF or any function + it calls invokes <c>enif_make_badarg</c>, the runtime ensures that a + <c>badarg</c> exception is raised when the NIF returns, even if the NIF + attempts to return a non-exception term instead. + The return value from <c>enif_make_badarg</c> may only be used as + return value from the NIF that invoked it (direct or indirectly) + or be passed to + <seealso marker="#enif_is_exception">enif_is_exception</seealso>, but + not to any other NIF API function.</p> + <p>See also: <seealso marker="#enif_has_pending_exception">enif_has_pending_exception</seealso>. + </p> + <note><p>In earlier versions (older than erts-7.0, OTP 18) the return value + from <c>enif_make_badarg</c> had to be returned from the NIF. This + requirement is now lifted as the return value from the NIF is ignored + if <c>enif_make_badarg</c> has been invoked.</p></note></desc> </func> <func><name><ret>ERL_NIF_TERM</ret><nametext>enif_make_binary(ErlNifEnv* env, ErlNifBinary* bin)</nametext></name> <fsummary>Make a binary term.</fsummary> @@ -931,7 +923,10 @@ typedef enum { </func> <func><name><ret>ERL_NIF_TERM</ret><nametext>enif_make_double(ErlNifEnv* env, double d)</nametext></name> <fsummary>Create a floating-point term</fsummary> - <desc><p>Create a floating-point term from a <c>double</c>.</p></desc> + <desc><p>Create a floating-point term from a <c>double</c>. If the <c>double</c> argument is + not finite or is NaN, <c>enif_make_double</c> invokes + <seealso marker="#enif_make_badarg">enif_make_badarg</seealso>. + </p></desc> </func> <func><name><ret>int</ret><nametext>enif_make_existing_atom(ErlNifEnv* env, const char* name, ERL_NIF_TERM* atom, ErlNifCharEncoding encode)</nametext></name> <fsummary>Create an existing atom term</fsummary> @@ -939,7 +934,9 @@ typedef enum { the null-terminated C-string <c>name</c> with encoding <seealso marker="#ErlNifCharEncoding">encode</seealso>. If the atom already exists store the term in <c>*atom</c> and return true, otherwise - return false.</p></desc> + return false. If the length of <c>name</c> exceeds the maximum length + allowed for an atom (255 characters), <c>enif_make_existing_atom</c> + returns false.</p></desc> </func> <func><name><ret>int</ret><nametext>enif_make_existing_atom_len(ErlNifEnv* env, const char* name, size_t len, ERL_NIF_TERM* atom, ErlNifCharEncoding encoding)</nametext></name> <fsummary>Create an existing atom term</fsummary> @@ -947,7 +944,9 @@ typedef enum { string <c>name</c> with length <c>len</c> and encoding <seealso marker="#ErlNifCharEncoding">encode</seealso>. Null-characters are treated as any other characters. If the atom already exists store the term - in <c>*atom</c> and return true, otherwise return false.</p></desc> + in <c>*atom</c> and return true, otherwise return false. If <c>len</c> is greater + than the maximum length allowed for an atom (255 characters), + <c>enif_make_existing_atom_len</c> returns false.</p></desc> </func> <func><name><ret>ERL_NIF_TERM</ret><nametext>enif_make_int(ErlNifEnv* env, int i)</nametext></name> <fsummary>Create an integer term</fsummary> |