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Diffstat (limited to 'erts/doc/src/erl_nif.xml')
| -rw-r--r-- | erts/doc/src/erl_nif.xml | 931 |
1 files changed, 799 insertions, 132 deletions
diff --git a/erts/doc/src/erl_nif.xml b/erts/doc/src/erl_nif.xml index 864b91946a..f3921f1922 100644 --- a/erts/doc/src/erl_nif.xml +++ b/erts/doc/src/erl_nif.xml @@ -1,23 +1,24 @@ -<?xml version="1.0" encoding="latin1" ?> +<?xml version="1.0" encoding="utf-8" ?> <!DOCTYPE cref SYSTEM "cref.dtd"> <cref> <header> <copyright> - <year>2001</year><year>2013</year> + <year>2001</year><year>2016</year> <holder>Ericsson AB. All Rights Reserved.</holder> </copyright> <legalnotice> - The contents of this file are subject to the Erlang Public License, - Version 1.1, (the "License"); you may not use this file except in - compliance with the License. You should have received a copy of the - Erlang Public License along with this software. If not, it can be - retrieved online at http://www.erlang.org/. - - Software distributed under the License is distributed on an "AS IS" - basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See - the License for the specific language governing rights and limitations - under the License. + Licensed under the Apache License, Version 2.0 (the "License"); + you may not use this file except in compliance with the License. + You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + + Unless required by applicable law or agreed to in writing, software + distributed under the License is distributed on an "AS IS" BASIS, + WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + See the License for the specific language governing permissions and + limitations under the License. </legalnotice> @@ -66,34 +67,6 @@ </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"> @@ -165,23 +138,6 @@ ok automatically unloaded when the module code that it belongs to is purged by the code server.</p> - <p><marker id="lengthy_work"/> - As mentioned in the <seealso marker="#WARNING">warning</seealso> text at - the beginning of this document it is of vital importance that a native function - does return relatively fast. It is hard to give an exact maximum amount - of time that a native function is allowed to work, but as a rule of thumb - a well behaving native function should return to its caller before a - millisecond has passed. This can be achieved using different approaches. - If you have full control over the code that are to execute in the native - function, the best approach is to divide the work into multiple chunks of - work and call the native function multiple times. Function - <seealso marker="#enif_consume_timeslice">enif_consume_timeslice</seealso> can be - used this facilitate such work division. In some cases, however, this might not - be possible, e.g. when calling third party libraries. Then you typically want - to dispatch the work to another thread, return - from the native function, and wait for the result. The thread can send - the result back to the calling thread using message passing. Information - about thread primitives can be found below.</p> </description> <section> <title>FUNCTIONALITY</title> @@ -312,6 +268,220 @@ ok <p>The library initialization callbacks <c>load</c>, <c>reload</c> and <c>upgrade</c> are all thread-safe even for shared state data.</p> </item> + + <tag><marker id="version_management"/>Version Management</tag> + <item><p> + When a NIF library is built, information about NIF API version + is compiled into the library. When a NIF library is loaded the + runtime system verifies that the library is of a compatible version. + <c>erl_nif.h</c> defines <c>ERL_NIF_MAJOR_VERSION</c>, and + <c>ERL_NIF_MINOR_VERSION</c>. <c>ERL_NIF_MAJOR_VERSION</c> will be + incremented when NIF library incompatible changes are made to the + Erlang runtime system. Normally it will suffice to recompile the NIF + library when the <c>ERL_NIF_MAJOR_VERSION</c> has changed, but it + could, under rare circumstances, mean that NIF libraries have to + be slightly modified. If so, this will of course be documented. + <c>ERL_NIF_MINOR_VERSION</c> will be incremented when + new features are added. The runtime system uses the minor version + to determine what features to use. + </p><p> + The runtime system will normally refuse to load a NIF library if + the major versions differ, or if the major versions are equal and + the minor version used by the NIF library is greater than the one + used by the runtime system. Old NIF libraries with lower major + versions will however be allowed after a bump of the major version + during a transition period of two major releases. Such old NIF + libraries might however fail if deprecated features are used. + </p></item> + + <tag><marker id="time_measurement"/>Time Measurement</tag> + <item><p>Support for time measurement in NIF libraries:</p> + <list> + <item><seealso marker="#ErlNifTime"><c>ErlNifTime</c></seealso></item> + <item><seealso marker="#ErlNifTimeUnit"><c>ErlNifTimeUnit</c></seealso></item> + <item><seealso marker="#enif_monotonic_time"><c>enif_monotonic_time()</c></seealso></item> + <item><seealso marker="#enif_time_offset"><c>enif_time_offset()</c></seealso></item> + <item><seealso marker="#enif_convert_time_unit"><c>enif_convert_time_unit()</c></seealso></item> + </list> + </item> + + <tag><marker id="lengthy_work"/>Long-running NIFs</tag> + + <item><p> + As mentioned in the <seealso marker="#WARNING">warning</seealso> text at + the beginning of this document it is of <em>vital importance</em> that a + native function return relatively quickly. It is hard to give an exact + maximum amount of time that a native function is allowed to work, but as a + rule of thumb a well-behaving native function should return to its caller + before a millisecond has passed. This can be achieved using different + approaches. If you have full control over the code to execute in the + native function, the best approach is to divide the work into multiple + chunks of work and call the native function multiple times. In some + cases this might however not always be possible, e.g. when calling + third-party libraries.</p> + + <p>The + <seealso marker="#enif_consume_timeslice">enif_consume_timeslice()</seealso> + function can be used to inform the runtime system about the length of the + NIF call. It should typically always be used unless the NIF executes very + quickly.</p> + + <p>If the NIF call is too lengthy one needs to handle this in one of the + following ways in order to avoid degraded responsiveness, scheduler load + balancing problems, and other strange behaviors:</p> + + <taglist> + <tag>Yielding NIF</tag> + <item> + <p> + If the functionality of a long-running NIF can be split so that + its work can be achieved through a series of shorter NIF calls, + the application can either make that series of NIF calls from the + Erlang level, or it can call a NIF that first performs a chunk of + the work, then invokes the + <seealso marker="#enif_schedule_nif">enif_schedule_nif</seealso> + function to schedule another NIF call to perform the next chunk. + The final call scheduled in this manner can then return the + overall result. Breaking up a long-running function in + this manner enables the VM to regain control between calls to the + NIFs. + </p> + <p> + This approach is always preferred over the other alternatives + described below. This both from a performance perspective and + a system characteristics perspective. + </p> + </item> + + <tag>Threaded NIF</tag> + <item> + <p> + This is accomplished by dispatching the work to another thread + managed by the NIF library, return from the NIF, and wait for the + result. The thread can send the result back to the Erlang + process using <seealso marker="#enif_send">enif_send</seealso>. + Information about thread primitives can be found below. + </p> + </item> + + <tag><marker id="dirty_nifs"/>Dirty NIF</tag> + <item> + + <note> + <p> + <em>The dirty NIF functionality described here + is experimental</em>. Dirty NIF support is available only when + the emulator is configured with dirty schedulers enabled. This + feature is currently disabled by default. The Erlang runtime + without SMP support do not support dirty schedulers even when + the dirty scheduler support has been enabled. To check at + runtime for the presence of dirty scheduler threads, code can + use the + <seealso marker="#enif_system_info"><c>enif_system_info()</c></seealso> + API function. + </p> + </note> + + <p> + A NIF that cannot be split and cannot execute in a millisecond or + less is called a "dirty NIF" because it performs work that the + ordinary schedulers of the Erlang runtime system cannot handle cleanly. + Applications that make use of such functions must indicate to the + runtime that the functions are dirty so they can be handled + specially. This is handled by executing dirty jobs on a separate + set of schedulers called dirty schedulers. A dirty NIF executing + on a dirty scheduler does not have the same duration restriction + as a normal NIF. + </p> + + <p> + It is important to classify the dirty job correct. An I/O bound + job should be classified as such, and a CPU bound job should be + classified as such. If you should classify CPU bound jobs + as I/O bound jobs, dirty I/O schedulers might starve ordinary + schedulers. I/O bound jobs are expected to either block waiting + for I/O, and/or spend a limited amount of time moving data. + </p> + + <p> + To schedule a dirty NIF for execution, the appropriate + <c>flags</c> value can be set for the NIF in its + <seealso marker="#ErlNifFunc"><c>ErlNifFunc</c></seealso> + entry, or the application can call + <seealso marker="#enif_schedule_nif"><c>enif_schedule_nif</c></seealso>, + passing to it a pointer to the dirty NIF to be executed and + indicating with the <c>flags</c> argument whether it expects the + operation to be CPU-bound or I/O-bound. A job that alternates + between I/O bound and CPU bound can be reclassified and + rescheduled using <c>enif_schedule_nif</c> so that it executes on + the correct type of dirty scheduler at all times. For more + information see the documentation of the <c>erl</c> command line + arguments <seealso marker="erl#+SDcpu"><c>+SDcpu</c></seealso>, + and <seealso marker="erl#+SDio"><c>+SDio</c></seealso>. + </p> + + <p> + While a process is executing a dirty NIF some operations that + communicate with it may take a very long time to complete. + Suspend, or garbage collection of a process executing a dirty + NIF cannot be done until the dirty NIF has returned, so other + processes waiting for such operations to complete might have to + wait for a very long time. Blocking multi scheduling, i.e., + calling + <seealso marker="erlang#system_flag_multi_scheduling"><c>erlang:system_flag(multi_scheduling, + block)</c></seealso>, might also take a very long time to + complete. This since all ongoing dirty operations on all + dirty schedulers need to complete before the block + operation can complete. + </p> + + <p> + A lot of operations communicating with a process executing a + dirty NIF can, however, complete while it is executing the + dirty NIF. For example, retrieving information about it via + <c>process_info()</c>, setting its group leader, + register/unregister its name, etc. + </p> + + <p> + Termination of a process executing a dirty NIF can only be + completed up to a certain point while it is executing the + dirty NIF. All Erlang resources such as its registered name, + its ETS tables, etc will be released. All links and monitors + will be triggered. The actual execution of the NIF will + however <em>not</em> be stopped. The NIF can safely continue + execution, allocate heap memory, etc, but it is of course better + to stop executing as soon as possible. The NIF can check + whether current process is alive or not using + <seealso marker="#enif_is_current_process_alive"><c>enif_is_current_process_alive</c></seealso>. + Communication using + <seealso marker="#enif_send"><c>enif_send</c></seealso>, + and <seealso marker="#enif_port_command"><c>enif_port_command</c></seealso> + will also be dropped when the sending process is not alive. + Deallocation of certain internal resources such as process + heap, and process control block will be delayed until the + dirty NIF has completed. + </p> + + <p>Currently known issues that are planned to be fixed:</p> + <list> + <item> + <p> + Since purging of a module currently might need to garbage + collect a process in order to determine if it has + references to the module, a process executing a dirty + NIF might delay purging for a very long time. Delaying + a purge operation implies delaying <em>all</em> code + loading operations which might cause severe problems for + the system as a whole. + </p> + </item> + </list> + + </item> + </taglist> + + </item> </taglist> </section> <section> @@ -330,6 +500,8 @@ ok <c>upgrade</c> will be called to initialize the library. <c>unload</c> is called to release the library. They are all described individually below.</p> + <p>If compiling a nif for static inclusion via --enable-static-nifs you + have to define STATIC_ERLANG_NIF before the ERL_NIF_INIT declaration.</p> </item> <tag><marker id="load"/>int (*load)(ErlNifEnv* env, void** priv_data, ERL_NIF_TERM load_info)</tag> @@ -367,13 +539,15 @@ ok </item> <tag><marker id="reload"/>int (*reload)(ErlNifEnv* env, void** priv_data, ERL_NIF_TERM load_info)</tag> - <note><p>The reload mechanism is <em>deprecated</em>. It was only intended - as a development feature. Do not use it as an upgrade method for - live production systems. It might be removed in future releases. Be sure - to pass <c>reload</c> as <c>NULL</c> to <seealso marker="#ERL_NIF_INIT">ERL_NIF_INIT</seealso> - to disable it when not used.</p> - </note> - <item><p><c>reload</c> is called when the NIF library is loaded + + <item> + <note><p>The reload mechanism is <em>deprecated</em>. It was only intended + as a development feature. Do not use it as an upgrade method for + live production systems. It might be removed in future releases. Be sure + to pass <c>reload</c> as <c>NULL</c> to <seealso marker="#ERL_NIF_INIT">ERL_NIF_INIT</seealso> + to disable it when not used.</p> + </note> + <p><c>reload</c> is called when the NIF library is loaded and there is already a previously loaded library for this module code.</p> <p>Works the same as <c>load</c>. The only difference is that @@ -422,8 +596,9 @@ ok independent environment with all its terms is valid until you explicitly invalidates it with <seealso marker="#enif_free_env">enif_free_env</seealso> or <c>enif_send</c>.</p> - <p>All elements of a list/tuple must belong to the same environment as the - list/tuple itself. Terms can be copied between environments with + <p>All contained terms of a list/tuple/map must belong to the same + environment as the list/tuple/map itself. Terms can be copied between + environments with <seealso marker="#enif_make_copy">enif_make_copy</seealso>.</p> </item> <tag><marker id="ErlNifFunc"/>ErlNifFunc</tag> @@ -431,9 +606,10 @@ ok <p/> <code type="none"> typedef struct { - const char* <em>name</em>; - unsigned <em>arity</em>; - ERL_NIF_TERM (*<em>fptr</em>)(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]); + const char* name; + unsigned arity; + ERL_NIF_TERM (*fptr)(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]); + unsigned flags; } ErlNifFunc; </code> <p>Describes a NIF by its name, arity and implementation. @@ -444,15 +620,29 @@ typedef struct { will thus denote the Nth argument to the NIF. Note that the <c>argc</c> argument allows for the same C function to implement several Erlang functions with different arity (but - same name probably).</p> + same name probably). For a regular NIF, <c>flags</c> is 0 (and + so its value can be omitted for statically initialized <c>ErlNifFunc</c> + instances), or it can be used to indicate that the NIF is a <seealso + marker="#dirty_nifs">dirty NIF</seealso> that should be executed + on a dirty scheduler thread (<em>note that the dirty NIF functionality + described here is experimental</em> and that you have to enable + support for dirty schedulers when building OTP in order to try the + functionality out). If the dirty NIF is expected to be + CPU-bound, its <c>flags</c> field should be set to + <c>ERL_NIF_DIRTY_JOB_CPU_BOUND</c>, or for I/O-bound jobs, + <c>ERL_NIF_DIRTY_JOB_IO_BOUND</c>.</p> + <note><p>If one of the + <c>ERL_NIF_DIRTY_JOB_*_BOUND</c> flags is set, and the runtime + system has no support for dirty schedulers, the runtime system + will refuse to load the NIF library.</p></note> </item> <tag><marker id="ErlNifBinary"/>ErlNifBinary</tag> <item> <p/> <code type="none"> typedef struct { - unsigned <em>size</em>; - unsigned char* <em>data</em>; + unsigned size; + unsigned char* data; } ErlNifBinary; </code> <p><c>ErlNifBinary</c> contains transient information about an @@ -461,6 +651,18 @@ typedef struct { <p>Note that <c>ErlNifBinary</c> is a semi-opaque type and you are only allowed to read fields <c>size</c> and <c>data</c>.</p> </item> + + <tag><marker id="ErlNifBinaryToTerm"/>ErlNifBinaryToTerm</tag> + <item> + <p>An enumeration of the options that can be given to + <seealso marker="#enif_binary_to_term">enif_binary_to_term</seealso>. + For default behavior, use the value <c>0</c>.</p> + <taglist> + <tag><c>ERL_NIF_BIN2TERM_SAFE</c></tag> + <item><p>Use this option when receiving data from untrusted sources.</p></item> + </taglist> + </item> + <tag><marker id="ErlNifPid"/>ErlNifPid</tag> <item> <p><c>ErlNifPid</c> is a process identifier (pid). In contrast to @@ -469,6 +671,14 @@ typedef struct { <seealso marker="#ErlNifEnv">environment</seealso>. <c>ErlNifPid</c> is an opaque type.</p> </item> + <tag><marker id="ErlNifPort"/>ErlNifPort</tag> + <item> + <p><c>ErlNifPort</c> is a port identifier. In contrast to + port id terms (instances of <c>ERL_NIF_TERM</c>), <c>ErlNifPort</c>'s are self + contained and not bound to any + <seealso marker="#ErlNifEnv">environment</seealso>. <c>ErlNifPort</c> + is an opaque type.</p> + </item> <tag><marker id="ErlNifResourceType"/>ErlNifResourceType</tag> <item> @@ -483,8 +693,7 @@ typedef struct { <code type="none"> typedef void ErlNifResourceDtor(ErlNifEnv* env, void* obj); </code> - <p>The function prototype of a resource destructor function. - A destructor function is not allowed to call any term-making functions.</p> + <p>The function prototype of a resource destructor function.</p> </item> <tag><marker id="ErlNifCharEncoding"/>ErlNifCharEncoding</tag> <item> @@ -508,17 +717,51 @@ typedef enum { <item><p>A native signed 64-bit integer type.</p></item> <tag><marker id="ErlNifUInt64"/>ErlNifUInt64</tag> <item><p>A native unsigned 64-bit integer type.</p></item> + + <tag><marker id="ErlNifTime"/>ErlNifTime</tag> + <item> + <p>A signed 64-bit integer type for representation of time.</p> + </item> + <tag><marker id="ErlNifTimeUnit"/>ErlNifTimeUnit</tag> + <item> + <p>An enumeration of time units supported by the NIF API:</p> + <taglist> + <tag><c>ERL_NIF_SEC</c></tag> + <item><p>Seconds</p></item> + <tag><c>ERL_NIF_MSEC</c></tag> + <item><p>Milliseconds</p></item> + <tag><c>ERL_NIF_USEC</c></tag> + <item><p>Microseconds</p></item> + <tag><c>ERL_NIF_NSEC</c></tag> + <item><p>Nanoseconds</p></item> + </taglist> + </item> + + <tag><marker id="ErlNifUniqueInteger"/>ErlNifUniqueInteger</tag> + <item> + <p>An enumeration of the properties that can be requested from + <seealso marker="#enif_make_unique_integer">enif_unique_integer</seealso>. + For default properties, use the value <c>0</c>.</p> + <taglist> + <tag><c>ERL_NIF_UNIQUE_POSITIVE</c></tag> + <item><p>Return only positive integers</p></item> + <tag><c>ERL_NIF_UNIQUE_MONOTONIC</c></tag> + <item><p>Return only + <seealso marker="time_correction#Strictly_Monotonically_Increasing">strictly + monotonically increasing</seealso> integer corresponding to creation time</p></item> + </taglist> + </item> </taglist> </section> <funcs> <func><name><ret>void *</ret><nametext>enif_alloc(size_t size)</nametext></name> - <fsummary>Allocate dynamic memory.</fsummary> + <fsummary>Allocate dynamic memory</fsummary> <desc><p>Allocate memory of <c>size</c> bytes. Return NULL if allocation failed.</p></desc> </func> <func><name><ret>int</ret><nametext>enif_alloc_binary(size_t size, ErlNifBinary* bin)</nametext></name> - <fsummary>Create a new binary.</fsummary> + <fsummary>Create a new binary</fsummary> <desc><p>Allocate a new binary of size <c>size</c> bytes. Initialize the structure pointed to by <c>bin</c> to refer to the allocated binary. The binary must either be released by @@ -545,11 +788,30 @@ typedef enum { <desc><p>Allocate a memory managed resource object of type <c>type</c> and size <c>size</c> bytes.</p></desc> </func> <func><name><ret>void</ret><nametext>enif_clear_env(ErlNifEnv* env)</nametext></name> - <fsummary>Clear an environment for reuse.</fsummary> + <fsummary>Clear an environment for reuse</fsummary> <desc><p>Free all terms in an environment and clear it for reuse. The environment must have been allocated with <seealso marker="#enif_alloc_env">enif_alloc_env</seealso>. </p></desc> </func> + <func><name><ret>size_t</ret><nametext>enif_binary_to_term(ErlNifEnv *env, const unsigned char* data, size_t size, ERL_NIF_TERM *term, ErlNifBinaryToTerm opts)</nametext></name> + <fsummary>Create a term from the external format</fsummary> + <desc> + <p>Create a term that is the result of decoding the binary data + at <c>data</c>, which must be encoded according to the Erlang external term format. + No more than <c>size</c> bytes are read from <c>data</c>. Argument <c>opts</c> + correspond to the second argument to <seealso marker="erlang#binary_to_term-2"> + <c>erlang:binary_to_term/2</c></seealso>, and must be either <c>0</c> or + <c>ERL_NIF_BIN2TERM_SAFE</c>.</p> + <p>On success, store the resulting term at <c>*term</c> and return + the actual number of bytes read. Return zero if decoding fails or if <c>opts</c> + is invalid.</p> + <p>See also: + <seealso marker="#ErlNifBinaryToTerm"><c>ErlNifBinaryToTerm</c></seealso>, + <seealso marker="erlang#binary_to_term-2"><c>erlang:binary_to_term/2</c></seealso> and + <seealso marker="#enif_term_to_binary"><c>enif_term_to_binary</c></seealso>. + </p> + </desc> + </func> <func><name><ret>int</ret><nametext>enif_compare(ERL_NIF_TERM lhs, ERL_NIF_TERM rhs)</nametext></name> <fsummary>Compare two terms</fsummary> <desc><p>Return an integer less than, equal to, or greater than @@ -607,7 +869,48 @@ typedef enum { a number of repeated NIF-calls without the need to create threads. See also the <seealso marker="#WARNING">warning</seealso> text at the beginning of this document.</p> </desc> + + </func> + + <func> + <name><ret>ErlNifTime</ret><nametext>enif_convert_time_unit(ErlNifTime val, ErlNifTimeUnit from, ErlNifTimeUnit to)</nametext></name> + <fsummary>Convert time unit of a time value</fsummary> + <desc> + <marker id="enif_convert_time_unit"></marker> + <p>Arguments:</p> + <taglist> + <tag><c>val</c></tag> + <item>Value to convert time unit for.</item> + <tag><c>from</c></tag> + <item>Time unit of <c>val</c>.</item> + <tag><c>to</c></tag> + <item>Time unit of returned value.</item> + </taglist> + <p>Converts the <c>val</c> value of time unit <c>from</c> to + the corresponding value of time unit <c>to</c>. The result is + rounded using the floor function.</p> + <p>Returns <c>ERL_NIF_TIME_ERROR</c> if called with an invalid + time unit argument.</p> + <p>See also: + <seealso marker="#ErlNifTime"><c>ErlNifTime</c></seealso> and + <seealso marker="#ErlNifTimeUnit"><c>ErlNifTimeUnit</c></seealso>. + </p> + </desc> + </func> + + <func> + <name><ret>ERL_NIF_TERM</ret><nametext>enif_cpu_time(ErlNifEnv *)</nametext></name> + <fsummary></fsummary> + <desc> + <p>Returns the CPU time in the same format as <seealso marker="erlang#timestamp-0">erlang:timestamp()</seealso>. + The CPU time is the time the current logical cpu has spent executing since + some arbitrary point in the past. + If the OS does not support fetching of this value <c>enif_cpu_time</c> + invokes <seealso marker="#enif_make_badarg">enif_make_badarg</seealso>. + </p> + </desc> </func> + <func><name><ret>int</ret><nametext>enif_equal_tids(ErlNifTid tid1, ErlNifTid tid2)</nametext></name> <fsummary></fsummary> <desc><p>Same as <seealso marker="erl_driver#erl_drv_equal_tids">erl_drv_equal_tids</seealso>. @@ -633,14 +936,14 @@ typedef enum { <c>size-1</c>.</p></desc> </func> <func><name><ret>int</ret><nametext>enif_get_atom_length(ErlNifEnv* env, ERL_NIF_TERM term, unsigned* len, ErlNifCharEncoding encode)</nametext></name> - <fsummary>Get the length of atom <c>term</c>.</fsummary> + <fsummary>Get the length of atom <c>term</c></fsummary> <desc><p>Set <c>*len</c> to the length (number of bytes excluding terminating null character) of the atom <c>term</c> with encoding <c>encode</c>. Return true on success or false if <c>term</c> is not an atom.</p></desc> </func> <func><name><ret>int</ret><nametext>enif_get_double(ErlNifEnv* env, ERL_NIF_TERM term, double* dp)</nametext></name> - <fsummary>Read a floating-point number term.</fsummary> + <fsummary>Read a floating-point number term</fsummary> <desc><p>Set <c>*dp</c> to the floating point value of <c>term</c>. Return true on success or false if <c>term</c> is not a float.</p></desc> </func> @@ -662,6 +965,12 @@ typedef enum { pid variable <c>*pid</c> from it and return true. Otherwise return false. No check if the process is alive is done.</p></desc> </func> + <func><name><ret>int</ret><nametext>enif_get_local_port(ErlNifEnv* env, ERL_NIF_TERM term, ErlNifPort* port_id)</nametext></name> + <fsummary>Read an local port term</fsummary> + <desc><p>If <c>term</c> identifies a node local port, initialize the + port variable <c>*port_id</c> from it and return true. Otherwise return false. + No check if the port is alive is done.</p></desc> + </func> <func><name><ret>int</ret><nametext>enif_get_list_cell(ErlNifEnv* env, ERL_NIF_TERM list, ERL_NIF_TERM* head, ERL_NIF_TERM* tail)</nametext></name> <fsummary>Get head and tail from a list</fsummary> <desc><p>Set <c>*head</c> and <c>*tail</c> from @@ -669,17 +978,28 @@ typedef enum { non-empty list.</p></desc> </func> <func><name><ret>int</ret><nametext>enif_get_list_length(ErlNifEnv* env, ERL_NIF_TERM term, unsigned* len)</nametext></name> - <fsummary>Get the length of list <c>term</c>.</fsummary> + <fsummary>Get the length of list <c>term</c></fsummary> <desc><p>Set <c>*len</c> to the length of list <c>term</c> and return true, - or return false if <c>term</c> is not a list.</p></desc> + or return false if <c>term</c> is not a proper list.</p></desc> </func> <func><name><ret>int</ret><nametext>enif_get_long(ErlNifEnv* env, ERL_NIF_TERM term, long int* ip)</nametext></name> - <fsummary>Read an long integer term.</fsummary> + <fsummary>Read an long integer term</fsummary> <desc><p>Set <c>*ip</c> to the long integer value of <c>term</c> and return true, or return false if <c>term</c> is not an integer or is outside the bounds of type <c>long int</c>.</p></desc> </func> - <func><name><ret>int</ret><nametext>enif_get_resource(ErlNifEnv* env, ERL_NIF_TERM term, ErlNifResourceType* type, void** objp)</nametext></name> + <func><name><ret>int</ret><nametext>enif_get_map_size(ErlNifEnv* env, ERL_NIF_TERM term, size_t *size)</nametext></name> + <fsummary>Read the size of a map term</fsummary> + <desc><p>Set <c>*size</c> to the number of key-value pairs in the map <c>term</c> and + return true, or return false if <c>term</c> is not a map.</p></desc> + </func> + <func><name><ret>int</ret><nametext>enif_get_map_value(ErlNifEnv* env, ERL_NIF_TERM map, ERL_NIF_TERM key, ERL_NIF_TERM* value)</nametext></name> + <fsummary>Get the value of a key in a map</fsummary> + <desc><p>Set <c>*value</c> to the value associated with <c>key</c> in the + map <c>map</c> and return true. Return false if <c>map</c> is not a map + or if <c>map</c> does not contain <c>key</c>.</p></desc> + </func> + <func><name><ret>int</ret><nametext>enif_get_resource(ErlNifEnv* env, ERL_NIF_TERM term, ErlNifResourceType* type, void** objp)</nametext></name> <fsummary>Get the pointer to a resource object</fsummary> <desc><p>Set <c>*objp</c> to point to the resource object referred to by <c>term</c>.</p> <p>Return true on success or false if <c>term</c> is not a handle to a resource object @@ -688,7 +1008,7 @@ typedef enum { <func><name><ret>int</ret><nametext>enif_get_string(ErlNifEnv* env, ERL_NIF_TERM list, char* buf, unsigned size, ErlNifCharEncoding encode)</nametext></name> - <fsummary>Get a C-string from a list.</fsummary> + <fsummary>Get a C-string from a list</fsummary> <desc><p>Write a null-terminated string, in the buffer pointed to by <c>buf</c> with size <c>size</c>, consisting of the characters in the string <c>list</c>. The characters are written using encoding @@ -701,7 +1021,7 @@ typedef enum { <c>size</c> is less than 1.</p></desc> </func> <func><name><ret>int</ret><nametext>enif_get_tuple(ErlNifEnv* env, ERL_NIF_TERM term, int* arity, const ERL_NIF_TERM** array)</nametext></name> - <fsummary>Inspect the elements of a tuple.</fsummary> + <fsummary>Inspect the elements of a tuple</fsummary> <desc><p>If <c>term</c> is a tuple, set <c>*array</c> to point to an array containing the elements of the tuple and set <c>*arity</c> to the number of elements. Note that the array @@ -711,23 +1031,40 @@ typedef enum { tuple.</p></desc> </func> <func><name><ret>int</ret><nametext>enif_get_uint(ErlNifEnv* env, ERL_NIF_TERM term, unsigned int* ip)</nametext></name> - <fsummary>Read an unsigned integer term.</fsummary> + <fsummary>Read an unsigned integer term</fsummary> <desc><p>Set <c>*ip</c> to the unsigned integer value of <c>term</c> and return true, or return false if <c>term</c> is not an unsigned integer or is outside the bounds of type <c>unsigned int</c>.</p></desc> </func> <func><name><ret>int</ret><nametext>enif_get_uint64(ErlNifEnv* env, ERL_NIF_TERM term, ErlNifUInt64* ip)</nametext></name> - <fsummary>Read an unsigned 64-bit integer term.</fsummary> + <fsummary>Read an unsigned 64-bit integer term</fsummary> <desc><p>Set <c>*ip</c> to the unsigned integer value of <c>term</c> and return true, or return false if <c>term</c> is not an unsigned integer or is outside the bounds of an unsigned 64-bit integer.</p></desc> </func> <func><name><ret>int</ret><nametext>enif_get_ulong(ErlNifEnv* env, ERL_NIF_TERM term, unsigned long* ip)</nametext></name> - <fsummary>Read an unsigned integer term.</fsummary> + <fsummary>Read an unsigned integer term</fsummary> <desc><p>Set <c>*ip</c> to the unsigned long integer value of <c>term</c> 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_getenv(const char* key, char* value, size_t *value_size)</nametext></name> + <fsummary>Get the value of an environment variable</fsummary> + <desc><p>Same as <seealso marker="erl_driver#erl_drv_getenv">erl_drv_getenv</seealso>.</p></desc> + </func> + <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>. 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, &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> + and <seealso marker="#enif_raise_exception">enif_raise_exception</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 @@ -753,13 +1090,25 @@ typedef enum { <fsummary>Determine if a term is a binary</fsummary> <desc><p>Return true if <c>term</c> is a binary</p></desc> </func> + <func><name><ret>int</ret><nametext>enif_is_current_process_alive(ErlNifEnv* env)</nametext></name> + <fsummary>Determine if currently executing process is alive or not.</fsummary> + <desc><p>Return true if currently executing process is currently alive; otherwise + false.</p> + <p>This function can only be used from a NIF-calling thread, and with an + environment corresponding to currently executing processes.</p></desc> + </func> <func><name><ret>int</ret><nametext>enif_is_empty_list(ErlNifEnv* env, ERL_NIF_TERM term)</nametext></name> <fsummary>Determine if a term is an empty list</fsummary> <desc><p>Return true if <c>term</c> is an empty list.</p></desc> </func> - <marker id="enif_is_exception"/><func><name><ret>int</ret><nametext>enif_is_exception(ErlNifEnv* env, ERL_NIF_TERM term)</nametext></name> + <func><name><ret>int</ret><nametext>enif_is_exception(ErlNifEnv* env, ERL_NIF_TERM term)</nametext></name> <fsummary>Determine if a term is an exception</fsummary> - <desc><p>Return true if <c>term</c> is an exception.</p></desc> + <desc><marker id="enif_is_exception"/> + <p>Return true if <c>term</c> is an exception.</p></desc> + </func> + <func><name><ret>int</ret><nametext>enif_is_map(ErlNifEnv* env, ERL_NIF_TERM term)</nametext></name> + <fsummary>Determine if a term is a map</fsummary> + <desc><p>Return true if <c>term</c> is a map, false otherwise.</p></desc> </func> <func><name><ret>int</ret><nametext>enif_is_number(ErlNifEnv* env, ERL_NIF_TERM term)</nametext></name> <fsummary>Determine if a term is a number (integer or float)</fsummary> @@ -783,6 +1132,18 @@ typedef enum { <fsummary>Determine if a term is a port</fsummary> <desc><p>Return true if <c>term</c> is a port.</p></desc> </func> + <func><name><ret>int</ret><nametext>enif_is_port_alive(ErlNifEnv* env, ErlNifPort *port_id)</nametext></name> + <fsummary>Determine if a local port is alive or not.</fsummary> + <desc><p>Return true if <c>port_id</c> is currently alive.</p> + <p>This function is only thread-safe when the emulator with SMP support is used. + It can only be used in a non-SMP emulator from a NIF-calling thread.</p></desc> + </func> + <func><name><ret>int</ret><nametext>enif_is_process_alive(ErlNifEnv* env, ErlNifPid *pid)</nametext></name> + <fsummary>Determine if a local process is alive or not.</fsummary> + <desc><p>Return true if <c>pid</c> is currently alive.</p> + <p>This function is only thread-safe when the emulator with SMP support is used. + It can only be used in a non-SMP emulator from a NIF-calling thread.</p></desc> + </func> <func><name><ret>int</ret><nametext>enif_is_ref(ErlNifEnv* env, ERL_NIF_TERM term)</nametext></name> <fsummary>Determine if a term is a reference</fsummary> <desc><p>Return true if <c>term</c> is a reference.</p></desc> @@ -806,40 +1167,58 @@ 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> + <fsummary>Make a badarg exception</fsummary> + <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 be used only as the + return value from the NIF that invoked it (directly 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> + and <seealso marker="#enif_raise_exception">enif_raise_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> + <fsummary>Make a binary term</fsummary> <desc><p>Make a binary term from <c>bin</c>. Any ownership of the binary data will be transferred to the created term and <c>bin</c> should be considered read-only for the rest of the NIF call and then as released.</p></desc> </func> <func><name><ret>ERL_NIF_TERM</ret><nametext>enif_make_copy(ErlNifEnv* dst_env, ERL_NIF_TERM src_term)</nametext></name> - <fsummary>Make a copy of a term.</fsummary> + <fsummary>Make a copy of a term</fsummary> <desc><p>Make a copy of term <c>src_term</c>. The copy will be created in environment <c>dst_env</c>. The source term may be located in any environment.</p></desc> </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> @@ -847,7 +1226,9 @@ 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> @@ -855,7 +1236,9 @@ 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> @@ -866,7 +1249,7 @@ typedef enum { <desc><p>Create an integer term from a signed 64-bit integer.</p></desc> </func> <func><name><ret>ERL_NIF_TERM</ret><nametext>enif_make_list(ErlNifEnv* env, unsigned cnt, ...)</nametext></name> - <fsummary>Create a list term.</fsummary> + <fsummary>Create a list term</fsummary> <desc><p>Create an ordinary list term of length <c>cnt</c>. Expects <c>cnt</c> number of arguments (after <c>cnt</c>) of type ERL_NIF_TERM as the elements of the list. An empty list is returned if <c>cnt</c> is 0.</p></desc> @@ -880,28 +1263,21 @@ typedef enum { <name><ret>ERL_NIF_TERM</ret><nametext>enif_make_list7(ErlNifEnv* env, ERL_NIF_TERM e1, ..., ERL_NIF_TERM e7)</nametext></name> <name><ret>ERL_NIF_TERM</ret><nametext>enif_make_list8(ErlNifEnv* env, ERL_NIF_TERM e1, ..., ERL_NIF_TERM e8)</nametext></name> <name><ret>ERL_NIF_TERM</ret><nametext>enif_make_list9(ErlNifEnv* env, ERL_NIF_TERM e1, ..., ERL_NIF_TERM e9)</nametext></name> - <fsummary>Create a list term.</fsummary> + <fsummary>Create a list term</fsummary> <desc><p>Create an ordinary list term with length indicated by the function name. Prefer these functions (macros) over the variadic <c>enif_make_list</c> to get a compile time error if the number of arguments does not match.</p></desc> </func> <func><name><ret>ERL_NIF_TERM</ret><nametext>enif_make_list_cell(ErlNifEnv* env, ERL_NIF_TERM head, ERL_NIF_TERM tail)</nametext></name> - <fsummary>Create a list cell.</fsummary> + <fsummary>Create a list cell</fsummary> <desc><p>Create a list cell <c>[head | tail]</c>.</p></desc> </func> <func><name><ret>ERL_NIF_TERM</ret><nametext>enif_make_list_from_array(ErlNifEnv* env, const ERL_NIF_TERM arr[], unsigned cnt)</nametext></name> - <fsummary>Create a list term from an array.</fsummary> + <fsummary>Create a list term from an array</fsummary> <desc><p>Create an ordinary list containing the elements of array <c>arr</c> of length <c>cnt</c>. An empty list is returned if <c>cnt</c> is 0.</p></desc> </func> - <func><name><ret>int</ret><nametext>enif_make_reverse_list(ErlNifEnv* env, ERL_NIF_TERM term, ERL_NIF_TERM *list)</nametext></name> - <fsummary>Create the reverse list of the list <c>term</c>.</fsummary> - <desc><p>Set <c>*list</c> to the reverse list of the list <c>term</c> and return true, - or return false if <c>term</c> is not a list. This function should only be used on - short lists as a copy will be created of the list which will not be released until after the - nif returns.</p></desc> - </func> <func><name><ret>ERL_NIF_TERM</ret><nametext>enif_make_long(ErlNifEnv* env, long int i)</nametext></name> <fsummary>Create an integer term from a long int</fsummary> <desc><p>Create an integer term from a <c>long int</c>.</p></desc> @@ -916,12 +1292,42 @@ typedef enum { reallocated.</p><p>Return a pointer to the raw binary data and set <c>*termp</c> to the binary term.</p></desc> </func> + <func><name><ret>ERL_NIF_TERM</ret><nametext>enif_make_new_map(ErlNifEnv* env)</nametext></name> + <fsummary>Make an empty map term</fsummary> + <desc><p>Make an empty map term.</p></desc> + </func> + <func><name><ret>int</ret><nametext>enif_make_map_put(ErlNifEnv* env, ERL_NIF_TERM map_in, ERL_NIF_TERM key, ERL_NIF_TERM value, ERL_NIF_TERM* map_out)</nametext></name> + <fsummary>Insert key-value pair in map</fsummary> + <desc><p>Make a copy of map <c>map_in</c> and insert <c>key</c> with + <c>value</c>. If <c>key</c> already exists in <c>map_in</c>, the old + associated value is replaced by <c>value</c>. If successful set + <c>*map_out</c> to the new map and return true. Return false if + <c>map_in</c> is not a map.</p> + <p>The <c>map_in</c> term must belong to the environment <c>env</c>.</p></desc> + </func> + <func><name><ret>int</ret><nametext>enif_make_map_update(ErlNifEnv* env, ERL_NIF_TERM map_in, ERL_NIF_TERM key, ERL_NIF_TERM new_value, ERL_NIF_TERM* map_out)</nametext></name> + <fsummary>Replace value for key in map</fsummary> + <desc><p>Make a copy of map <c>map_in</c> and replace the old associated + value for <c>key</c> with <c>new_value</c>. If successful set + <c>*map_out</c> to the new map and return true. Return false if + <c>map_in</c> is not a map or if it does no contain <c>key</c>.</p> + <p>The <c>map_in</c> term must belong to the environment <c>env</c>.</p></desc> + </func> + <func><name><ret>int</ret><nametext>enif_make_map_remove(ErlNifEnv* env, ERL_NIF_TERM map_in, ERL_NIF_TERM key, ERL_NIF_TERM* map_out)</nametext></name> + <fsummary>Remove key from map</fsummary> + <desc><p>If map <c>map_in</c> contains <c>key</c>, make a copy of + <c>map_in</c> in <c>*map_out</c> and remove <c>key</c> and associated + value. If map <c>map_in</c> does not contain <c>key</c>, set + <c>*map_out</c> to <c>map_in</c>. Return true for success or false if + <c>map_in</c> is not a map.</p> + <p>The <c>map_in</c> term must belong to the environment <c>env</c>.</p></desc> + </func> <func><name><ret>ERL_NIF_TERM</ret><nametext>enif_make_pid(ErlNifEnv* env, const ErlNifPid* pid)</nametext></name> <fsummary>Make a pid term</fsummary> <desc><p>Make a pid term from <c>*pid</c>.</p></desc> </func> <func><name><ret>ERL_NIF_TERM</ret><nametext>enif_make_ref(ErlNifEnv* env)</nametext></name> - <fsummary>Create a reference.</fsummary> + <fsummary>Create a reference</fsummary> <desc><p>Create a reference like <seealso marker="erlang#make_ref-0">erlang:make_ref/0</seealso>.</p></desc> </func> <func><name><ret>ERL_NIF_TERM</ret><nametext>enif_make_resource(ErlNifEnv* env, void* obj)</nametext></name> @@ -959,20 +1365,28 @@ typedef enum { <seealso marker="#enif_release_resource">enif_release_resource</seealso>.</p> </desc> </func> + <func><name><ret>int</ret><nametext>enif_make_reverse_list(ErlNifEnv* env, ERL_NIF_TERM list_in, ERL_NIF_TERM *list_out)</nametext></name> + <fsummary>Create the reverse of a list</fsummary> + <desc><p>Set <c>*list_out</c> to the reverse list of the list <c>list_in</c> and return true, + or return false if <c>list_in</c> is not a list. This function should only be used on + short lists as a copy will be created of the list which will not be released until after the + nif returns.</p> + <p>The <c>list_in</c> term must belong to the environment <c>env</c>.</p></desc> + </func> <func><name><ret>ERL_NIF_TERM</ret><nametext>enif_make_string(ErlNifEnv* env, const char* string, ErlNifCharEncoding encoding)</nametext></name> - <fsummary>Create a string.</fsummary> + <fsummary>Create a string</fsummary> <desc><p>Create a list containing the characters of the null-terminated string <c>string</c> with encoding <seealso marker="#ErlNifCharEncoding">encoding</seealso>.</p></desc> </func> <func><name><ret>ERL_NIF_TERM</ret><nametext>enif_make_string_len(ErlNifEnv* env, const char* string, size_t len, ErlNifCharEncoding encoding)</nametext></name> - <fsummary>Create a string.</fsummary> + <fsummary>Create a string</fsummary> <desc><p>Create a list containing the characters of the string <c>string</c> with length <c>len</c> and encoding <seealso marker="#ErlNifCharEncoding">encoding</seealso>. Null-characters are treated as any other characters.</p></desc> </func> <func><name><ret>ERL_NIF_TERM</ret><nametext>enif_make_sub_binary(ErlNifEnv* env, ERL_NIF_TERM bin_term, size_t pos, size_t size)</nametext></name> - <fsummary>Make a subbinary term.</fsummary> + <fsummary>Make a subbinary term</fsummary> <desc><p>Make a subbinary of binary <c>bin_term</c>, starting at zero-based position <c>pos</c> with a length of <c>size</c> bytes. <c>bin_term</c> must be a binary or bitstring and @@ -980,7 +1394,7 @@ typedef enum { bytes in <c>bin_term</c>.</p></desc> </func> <func><name><ret>ERL_NIF_TERM</ret><nametext>enif_make_tuple(ErlNifEnv* env, unsigned cnt, ...)</nametext></name> - <fsummary>Create a tuple term.</fsummary> + <fsummary>Create a tuple term</fsummary> <desc><p>Create a tuple term of arity <c>cnt</c>. Expects <c>cnt</c> number of arguments (after <c>cnt</c>) of type ERL_NIF_TERM as the elements of the tuple.</p></desc> @@ -994,14 +1408,14 @@ typedef enum { <name><ret>ERL_NIF_TERM</ret><nametext>enif_make_tuple7(ErlNifEnv* env, ERL_NIF_TERM e1, ..., ERL_NIF_TERM e7)</nametext></name> <name><ret>ERL_NIF_TERM</ret><nametext>enif_make_tuple8(ErlNifEnv* env, ERL_NIF_TERM e1, ..., ERL_NIF_TERM e8)</nametext></name> <name><ret>ERL_NIF_TERM</ret><nametext>enif_make_tuple9(ErlNifEnv* env, ERL_NIF_TERM e1, ..., ERL_NIF_TERM e9)</nametext></name> - <fsummary>Create a tuple term.</fsummary> + <fsummary>Create a tuple term</fsummary> <desc><p>Create a tuple term with length indicated by the function name. Prefer these functions (macros) over the variadic <c>enif_make_tuple</c> to get a compile time error if the number of arguments does not match.</p></desc> </func> <func><name><ret>ERL_NIF_TERM</ret><nametext>enif_make_tuple_from_array(ErlNifEnv* env, const ERL_NIF_TERM arr[], unsigned cnt)</nametext></name> - <fsummary>Create a tuple term from an array.</fsummary> + <fsummary>Create a tuple term from an array</fsummary> <desc><p>Create a tuple containing the elements of array <c>arr</c> of length <c>cnt</c>.</p></desc> </func> @@ -1013,10 +1427,120 @@ typedef enum { <fsummary>Create an unsigned integer term</fsummary> <desc><p>Create an integer term from an unsigned 64-bit integer.</p></desc> </func> + <func> + <name><ret>ERL_NIF_TERM</ret><nametext>enif_make_unique_integer(ErlNifEnv *env, ErlNifUniqueInteger properties)</nametext></name> + <fsummary></fsummary> + <desc> + <p>Returns a unique integer with the same properties as given by <seealso marker="erlang#unique_integer-1">erlang:unique_integer/1</seealso>.</p> + <p><c>env</c> is the environment to create the integer in.</p> + <p> + <c>ERL_NIF_UNIQUE_POSITIVE</c> and <c>ERL_NIF_UNIQUE_MONOTONIC</c> can + be passed as the second argument to change the properties of the + integer returned. It is possible to combine them by or:ing the + two values together. + </p> + <p>See also: + <seealso marker="#ErlNifUniqueInteger"><c>ErlNifUniqueInteger</c></seealso>. + </p> + </desc> + </func> <func><name><ret>ERL_NIF_TERM</ret><nametext>enif_make_ulong(ErlNifEnv* env, unsigned long i)</nametext></name> <fsummary>Create an integer term from an unsigned long int</fsummary> <desc><p>Create an integer term from an <c>unsigned long int</c>.</p></desc> </func> + <func><name><ret>int</ret><nametext>enif_map_iterator_create(ErlNifEnv *env, ERL_NIF_TERM map, ErlNifMapIterator *iter, ErlNifMapIteratorEntry entry)</nametext></name> + <fsummary>Create a map iterator</fsummary> + <desc><p>Create an iterator for the map <c>map</c> by initializing the + structure pointed to by <c>iter</c>. The <c>entry</c> argument determines + the start position of the iterator: <c>ERL_NIF_MAP_ITERATOR_FIRST</c> or + <c>ERL_NIF_MAP_ITERATOR_LAST</c>. Return true on success or false if + <c>map</c> is not a map.</p> + <p>A map iterator is only useful during the lifetime of the environment + <c>env</c> that the <c>map</c> belongs to. The iterator must be destroyed by + calling <seealso marker="#enif_map_iterator_destroy"> + enif_map_iterator_destroy</seealso>.</p> + <code type="none"> +ERL_NIF_TERM key, value; +ErlNifMapIterator iter; +enif_map_iterator_create(env, my_map, &iter, ERL_NIF_MAP_ITERATOR_FIRST); + +while (enif_map_iterator_get_pair(env, &iter, &key, &value)) { + do_something(key,value); + enif_map_iterator_next(env, &iter); +} +enif_map_iterator_destroy(env, &iter); + </code> + <note><p>The key-value pairs of a map have no defined iteration + order. The only guarantee is that the iteration order of a single map + instance is preserved during the lifetime of the environment that the map + belongs to.</p> + </note> + </desc> + </func> + <func><name><ret>void</ret><nametext>enif_map_iterator_destroy(ErlNifEnv *env, ErlNifMapIterator *iter)</nametext></name> + <fsummary>Destroy a map iterator</fsummary> + <desc><p>Destroy a map iterator created by + <seealso marker="#enif_map_iterator_create">enif_map_iterator_create</seealso>. + </p></desc> + </func> + <func><name><ret>int</ret><nametext>enif_map_iterator_get_pair(ErlNifEnv *env, ErlNifMapIterator *iter, ERL_NIF_TERM *key, ERL_NIF_TERM *value)</nametext></name> + <fsummary>Get key and value at current map iterator position</fsummary> + <desc><p>Get key and value terms at current map iterator position. + On success set <c>*key</c> and <c>*value</c> and return true. + Return false if the iterator is positioned at head (before first entry) + or tail (beyond last entry).</p></desc> + </func> + <func><name><ret>int</ret><nametext>enif_map_iterator_is_head(ErlNifEnv *env, ErlNifMapIterator *iter)</nametext></name> + <fsummary>Check if map iterator is positioned before first</fsummary> + <desc><p>Return true if map iterator <c>iter</c> is positioned + before first entry.</p></desc> + </func> + <func><name><ret>int</ret><nametext>enif_map_iterator_is_tail(ErlNifEnv *env, ErlNifMapIterator *iter)</nametext></name> + <fsummary>Check if map iterator is positioned after last</fsummary> + <desc><p>Return true if map iterator <c>iter</c> is positioned + after last entry.</p></desc> + </func> + <func><name><ret>int</ret><nametext>enif_map_iterator_next(ErlNifEnv *env, ErlNifMapIterator *iter)</nametext></name> + <fsummary>Increment map iterator to point to next entry</fsummary> + <desc><p>Increment map iterator to point to next key-value entry. + Return true if the iterator is now positioned at a valid key-value entry, + or false if the iterator is positioned at the tail (beyond the last + entry).</p></desc> + </func> + <func><name><ret>int</ret><nametext>enif_map_iterator_prev(ErlNifEnv *env, ErlNifMapIterator *iter)</nametext></name> + <fsummary>Decrement map iterator to point to previous entry</fsummary> + <desc><p>Decrement map iterator to point to previous key-value entry. + Return true if the iterator is now positioned at a valid key-value entry, + or false if the iterator is positioned at the head (before the first + entry).</p></desc> + </func> + + <func> + <name><ret>ErlNifTime</ret><nametext>enif_monotonic_time(ErlNifTimeUnit time_unit)</nametext></name> + <fsummary>Get Erlang Monotonic Time</fsummary> + <desc> + <marker id="enif_monotonic_time"></marker> + <p>Arguments:</p> + <taglist> + <tag><c>time_unit</c></tag> + <item>Time unit of returned value.</item> + </taglist> + <p> + Returns the current + <seealso marker="time_correction#Erlang_Monotonic_Time">Erlang + monotonic time</seealso>. Note that it is not uncommon with + negative values. + </p> + <p>Returns <c>ERL_NIF_TIME_ERROR</c> if called with an invalid + time unit argument, or if called from a thread that is not a + scheduler thread.</p> + <p>See also: + <seealso marker="#ErlNifTime"><c>ErlNifTime</c></seealso> and + <seealso marker="#ErlNifTimeUnit"><c>ErlNifTimeUnit</c></seealso>. + </p> + </desc> + </func> + <func><name><ret>ErlNifMutex *</ret><nametext>enif_mutex_create(char *name)</nametext></name> <fsummary></fsummary> <desc><p>Same as <seealso marker="erl_driver#erl_drv_mutex_create">erl_drv_mutex_create</seealso>. @@ -1042,6 +1566,11 @@ typedef enum { <desc><p>Same as <seealso marker="erl_driver#erl_drv_mutex_unlock">erl_drv_mutex_unlock</seealso>. </p></desc> </func> + <func><name><ret>ERL_NIF_TERM</ret><nametext>enif_now_time(ErlNifEnv *env)</nametext></name> + <fsummary></fsummary> + <desc><p>Retuns an <seealso marker="erlang#now-0">erlang:now()</seealso> timestamp. + The enif_now_time function is <em>deprecated</em>.</p></desc> + </func> <func><name><ret>ErlNifResourceType *</ret><nametext>enif_open_resource_type(ErlNifEnv* env, const char* module_str, const char* name, ErlNifResourceDtor* dtor, ErlNifResourceFlags flags, ErlNifResourceFlags* tried)</nametext></name> @@ -1071,25 +1600,68 @@ typedef enum { and <seealso marker="#upgrade">upgrade</seealso>.</p> </desc> </func> + <func><name><ret>int</ret><nametext>enif_port_command(ErlNifEnv* env, const ErlNifPort* to_port, ErlNifEnv *msg_env, ERL_NIF_TERM msg)</nametext></name> + <fsummary>Send a port_command to to_port</fsummary> + <desc> + <p>This function works the same as <seealso marker="erlang#port_command-2">erlang:port_command/2</seealso> + except that it is always completely asynchronous.</p> + <taglist> + <tag><c>env</c></tag> + <item>The environment of the calling process. May not be NULL.</item> + <tag><c>*to_port</c></tag> + <item>The port id of the receiving port. The port id should refer to a + port on the local node.</item> + <tag><c>msg_env</c></tag> + <item>The environment of the message term. Can be a process + independent environment allocated with + <seealso marker="#enif_alloc_env">enif_alloc_env</seealso> or NULL.</item> + <tag><c>msg</c></tag> + <item>The message term to send. The same limitations apply as on the + payload to <seealso marker="erlang#port_command-2">erlang:port_command/2</seealso>.</item> + </taglist> + <p>Using a <c>msg_env</c> of NULL is an optimization which groups together + calls to <c>enif_alloc_env</c>, <c>enif_make_copy</c>, <c>enif_port_command</c> + and <c>enif_free_env</c> into one call. This optimization is only usefull + when a majority of the terms are to be copied from <c>env</c> to the <c>msg_env</c>.</p> + <p>This function return true if the command was successfully sent; otherwise, + false. The call may return false if it detects that the command failed for some + reason. For example, <c>*to_port</c> does not refer to a local port, if currently + executing process, i.e. the sender, is not alive, or if <c>msg</c> is invalid.</p> + <p>See also: <seealso marker="#enif_get_local_port"><c>enif_get_local_port</c></seealso>.</p> + </desc> + </func> <func><name><ret>void *</ret><nametext>enif_priv_data(ErlNifEnv* env)</nametext></name> <fsummary>Get the private data of a NIF library</fsummary> <desc><p>Return the pointer to the private data that was set by <c>load</c>, <c>reload</c> or <c>upgrade</c>.</p> <p>Was previously named <c>enif_get_data</c>.</p></desc> </func> + <func><name><ret>ERL_NIF_TERM</ret><nametext>enif_raise_exception(ErlNifEnv* env, ERL_NIF_TERM reason)</nametext></name> + <fsummary>Raise a NIF error exception</fsummary> + <desc><p>Create an error exception with the term <c>reason</c> 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_raise_exception</c>, the runtime ensures that the exception it creates + is raised when the NIF returns, even if the NIF attempts to return a non-exception + term instead. The return value from <c>enif_raise_exception</c> may be used only as + the return value from the NIF that invoked it (directly 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> + and <seealso marker="#enif_make_badarg">enif_make_badarg</seealso>.</p></desc> + </func> <func><name><ret>int</ret><nametext>enif_realloc_binary(ErlNifBinary* bin, size_t size)</nametext></name> - <fsummary>Change the size of a binary.</fsummary> + <fsummary>Change the size of a binary</fsummary> <desc><p>Change the size of a binary <c>bin</c>. The source binary may be read-only, in which case it will be left untouched and a mutable copy is allocated and assigned to <c>*bin</c>. Return true on success, false if memory allocation failed.</p></desc> </func> <func><name><ret>void</ret><nametext>enif_release_binary(ErlNifBinary* bin)</nametext></name> - <fsummary>Release a binary.</fsummary> + <fsummary>Release a binary</fsummary> <desc><p>Release a binary obtained from <c>enif_alloc_binary</c>.</p></desc> </func> <func><name><ret>void</ret><nametext>enif_release_resource(void* obj)</nametext></name> - <fsummary>Release a resource object.</fsummary> + <fsummary>Release a resource object</fsummary> <desc><p>Remove a reference to resource object <c>obj</c>obtained from <seealso marker="#enif_alloc_resource">enif_alloc_resource</seealso>. The resource object will be destructed when the last reference is removed. @@ -1139,13 +1711,38 @@ typedef enum { <desc><p>Same as <seealso marker="erl_driver#erl_drv_rwlock_tryrwlock">erl_drv_rwlock_tryrwlock</seealso>. </p></desc> </func> + <func><name><ret>ERL_NIF_TERM</ret><nametext>enif_schedule_nif(ErlNifEnv* env, const char* fun_name, int flags, ERL_NIF_TERM (*fp)(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]), int argc, const ERL_NIF_TERM argv[])</nametext></name> + <fsummary>Schedule a NIF for execution</fsummary> + <desc> + <p>Schedule NIF <c>fp</c> to execute. This function allows an application to break up long-running + work into multiple regular NIF calls or to schedule a <seealso marker="#dirty_nifs">dirty NIF</seealso> + to execute on a dirty scheduler thread (<em>note that the dirty NIF functionality described here is + experimental</em> and that you have to enable support for dirty schedulers when building OTP in + order to try the functionality out).</p> + <p>The <c>fun_name</c> argument provides a name for the NIF being scheduled for execution. If it cannot + be converted to an atom, <c>enif_schedule_nif</c> returns a <c>badarg</c> exception.</p> + <p>The <c>flags</c> argument must be set to 0 for a regular NIF, or if the emulator was built the + experimental dirty scheduler support enabled, <c>flags</c> can be set to either <c>ERL_NIF_DIRTY_JOB_CPU_BOUND</c> + if the job is expected to be CPU-bound, or <c>ERL_NIF_DIRTY_JOB_IO_BOUND</c> for jobs that will + be I/O-bound. If dirty scheduler threads are not available in the emulator, a try to schedule such a job + will result in a <c>badarg</c> exception.</p> + + <p>The <c>argc</c> and <c>argv</c> arguments can either be the originals passed into the calling NIF, or + they can be values created by the calling NIF.</p> + <p>The calling NIF must use the return value of <c>enif_schedule_nif</c> as its own return value.</p> + <p>Be aware that <c>enif_schedule_nif</c>, as its name implies, only schedules the + NIF for future execution. The calling NIF does not block waiting for the scheduled NIF to + execute and return, which means that the calling NIF can't expect to receive the scheduled NIF + return value and use it for further operations.</p> + </desc> + </func> <func><name><ret>ErlNifPid *</ret><nametext>enif_self(ErlNifEnv* caller_env, ErlNifPid* pid)</nametext></name> - <fsummary>Get the pid of the calling process.</fsummary> + <fsummary>Get the pid of the calling process</fsummary> <desc><p>Initialize the pid variable <c>*pid</c> to represent the calling process. Return <c>pid</c>.</p></desc> </func> <func><name><ret>int</ret><nametext>enif_send(ErlNifEnv* env, ErlNifPid* to_pid, ErlNifEnv* msg_env, ERL_NIF_TERM msg)</nametext></name> - <fsummary>Send a message to a process.</fsummary> + <fsummary>Send a message to a process</fsummary> <desc><p>Send a message to a process.</p> <taglist> <tag><c>env</c></tag> @@ -1156,17 +1753,23 @@ typedef enum { <tag><c>msg_env</c></tag> <item>The environment of the message term. Must be a process independent environment allocated with - <seealso marker="#enif_alloc_env">enif_alloc_env</seealso>.</item> + <seealso marker="#enif_alloc_env">enif_alloc_env</seealso> or NULL.</item> <tag><c>msg</c></tag> <item>The message term to send.</item> </taglist> - <p>Return true on success, or false if <c>*to_pid</c> does not refer to an alive local process.</p> + <p>Return true if the message was successfully sent; otherwise, false. The send + operation will fail if <c>*to_pid</c> does not refer to an alive local process, + or if currently executing process, i.e. the sender, is not alive.</p> <p>The message environment <c>msg_env</c> with all its terms (including <c>msg</c>) will be invalidated by a successful call to <c>enif_send</c>. The environment should either be freed with <seealso marker="#enif_free_env">enif_free_env</seealso> of cleared for reuse with <seealso marker="#enif_clear_env">enif_clear_env</seealso>.</p> + <p>If <c>msg_env</c> is set to NULL the <c>msg</c> term is copied and + the original term and its environemt is still valid after the call.</p> <p>This function is only thread-safe when the emulator with SMP support is used. It can only be used in a non-SMP emulator from a NIF-calling thread.</p> + <note><p>Passing <c>msg_env</c> as <c>NULL</c> is only supported since + erts-8.0 (OTP 19).</p></note> </desc> </func> <func><name><ret>unsigned</ret><nametext>enif_sizeof_resource(void* obj)</nametext></name> @@ -1174,12 +1777,33 @@ typedef enum { <desc><p>Get the byte size of a resource object <c>obj</c> obtained by <seealso marker="#enif_alloc_resource">enif_alloc_resource</seealso>.</p></desc> </func> + + <func><name><ret>int</ret><nametext>enif_snprintf(char *str, size_t size, const char *format, ...)</nametext></name> + <fsummary>Format strings and Erlang terms</fsummary> + <desc> + <p>Similar to <c>snprintf</c> but this format string also accepts <c>"%T"</c> which formats Erlang terms. + </p> + </desc> + </func> + <func> <name><ret>void</ret><nametext>enif_system_info(ErlNifSysInfo *sys_info_ptr, size_t size)</nametext></name> <fsummary>Get information about the Erlang runtime system</fsummary> <desc><p>Same as <seealso marker="erl_driver#driver_system_info">driver_system_info</seealso>. </p></desc> </func> + <func><name><ret>int</ret><nametext>enif_term_to_binary(ErlNifEnv *env, ERL_NIF_TERM term, ErlNifBinary *bin)</nametext></name> + <fsummary>Convert a term to the external format</fsummary> + <desc> + <p>Allocates a new binary with <seealso marker="#enif_alloc_binary">enif_alloc_binary</seealso> + and stores the result of encoding <c>term</c> according to the Erlang external term format.</p> + <p>Returns true on success or false if allocation failed.</p> + <p>See also: + <seealso marker="erlang#term_to_binary-1"><c>erlang:term_to_binary/1</c></seealso> and + <seealso marker="#enif_binary_to_term"><c>enif_binary_to_term</c></seealso>. + </p> + </desc> + </func> <func><name><ret>int</ret><nametext>enif_thread_create(char *name,ErlNifTid *tid,void * (*func)(void *),void *args,ErlNifThreadOpts *opts)</nametext></name> <fsummary></fsummary> <desc><p>Same as <seealso marker="erl_driver#erl_drv_thread_create">erl_drv_thread_create</seealso>. @@ -1210,6 +1834,50 @@ typedef enum { <desc><p>Same as <seealso marker="erl_driver#erl_drv_thread_self">erl_drv_thread_self</seealso>. </p></desc> </func> + <func><name><ret>int</ret><nametext>enif_thread_type(void)</nametext></name> + <fsummary>Determine type of current thread</fsummary> + <desc> + <p>Determine the type of currently executing thread. A positive value + indicates a scheduler thread while a negative value or zero indicates + another type of thread. Currently the following specific types exist + (which may be extended in the future):</p> + <taglist> + <tag><c>ERL_NIF_THR_UNDEFINED</c></tag> + <item><p>Undefined thread that is not a scheduler thread.</p></item> + <tag><c>ERL_NIF_THR_NORMAL_SCHEDULER</c></tag> + <item><p>A normal scheduler thread.</p></item> + <tag><c>ERL_NIF_THR_DIRTY_CPU_SCHEDULER</c></tag> + <item><p>A dirty CPU scheduler thread.</p></item> + <tag><c>ERL_NIF_THR_DIRTY_IO_SCHEDULER</c></tag> + <item><p>A dirty I/O scheduler thread.</p></item> + </taglist> + </desc> + </func> + <func> + <name><ret>ErlNifTime</ret><nametext>enif_time_offset(ErlNifTimeUnit time_unit)</nametext></name> + <fsummary>Get current Time Offset</fsummary> + <desc> + <marker id="enif_time_offset"></marker> + <p>Arguments:</p> + <taglist> + <tag><c>time_unit</c></tag> + <item>Time unit of returned value.</item> + </taglist> + <p>Returns the current time offset between + <seealso marker="time_correction#Erlang_Monotonic_Time">Erlang monotonic time</seealso> + and + <seealso marker="time_correction#Erlang_System_Time">Erlang system time</seealso> + converted into the <c>time_unit</c> passed as argument.</p> + <p>Returns <c>ERL_NIF_TIME_ERROR</c> if called with an invalid + time unit argument, or if called from a thread that is not a + scheduler thread.</p> + <p>See also: + <seealso marker="#ErlNifTime"><c>ErlNifTime</c></seealso> and + <seealso marker="#ErlNifTimeUnit"><c>ErlNifTimeUnit</c></seealso>. + </p> + </desc> + </func> + <func><name><ret>int</ret><nametext>enif_tsd_key_create(char *name, ErlNifTSDKey *key)</nametext></name> <fsummary></fsummary> <desc><p>Same as <seealso marker="erl_driver#erl_drv_tsd_key_create">erl_drv_tsd_key_create</seealso>. @@ -1236,4 +1904,3 @@ typedef enum { <p><seealso marker="erlang#load_nif-2">erlang:load_nif/2</seealso></p> </section> </cref> - |