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Diffstat (limited to 'erts/doc/src/erl_nif.xml')
| -rw-r--r-- | erts/doc/src/erl_nif.xml | 446 |
1 files changed, 426 insertions, 20 deletions
diff --git a/erts/doc/src/erl_nif.xml b/erts/doc/src/erl_nif.xml index 5a69bed34c..190ec12d0e 100644 --- a/erts/doc/src/erl_nif.xml +++ b/erts/doc/src/erl_nif.xml @@ -4,7 +4,7 @@ <cref> <header> <copyright> - <year>2001</year><year>2017</year> + <year>2001</year><year>2018</year> <holder>Ericsson AB. All Rights Reserved.</holder> </copyright> <legalnotice> @@ -194,7 +194,7 @@ ok <p>Binaries are sequences of whole bytes. Bitstrings with an arbitrary bit length have no support yet.</p> </item> - <tag>Resource objects</tag> + <tag><marker id="resource_objects"/>Resource objects</tag> <item> <p>The use of resource objects is a safe way to return pointers to native data structures from a NIF. A resource object is @@ -206,7 +206,7 @@ ok <seealso marker="#enif_make_resource"> <c>enif_make_resource</c></seealso>. The term returned by <c>enif_make_resource</c> is opaque in nature. - It can be stored and passed between processes on the same node, but + It can be stored and passed between processes, but the only real end usage is to pass it back as an argument to a NIF. The NIF can then call <seealso marker="#enif_get_resource"> <c>enif_get_resource</c></seealso> and get back a pointer to the @@ -344,6 +344,83 @@ return term;</code> <c>enif_convert_time_unit()</c></seealso></item> </list> </item> + <tag><marker id="enif_ioq"/>I/O Queues</tag> + <item> + <p>The Erlang nif library contains function for easily working + with I/O vectors as used by the unix system call <c>writev</c>. + The I/O Queue is not thread safe, so some other synchronization + mechanism has to be used.</p> + <list type="bulleted"> + <item><seealso marker="#SysIOVec"> + <c>SysIOVec</c></seealso></item> + <item><seealso marker="#ErlNifIOVec"> + <c>ErlNifIOVec</c></seealso></item> + <item><seealso marker="#enif_ioq_create"> + <c>enif_ioq_create()</c></seealso></item> + <item><seealso marker="#enif_ioq_destroy"> + <c>enif_ioq_destroy()</c></seealso></item> + <item><seealso marker="#enif_ioq_enq_binary"> + <c>enif_ioq_enq_binary()</c></seealso></item> + <item><seealso marker="#enif_ioq_enqv"> + <c>enif_ioq_enqv()</c></seealso></item> + <item><seealso marker="#enif_ioq_deq"> + <c>enif_ioq_deq()</c></seealso></item> + <item><seealso marker="#enif_ioq_peek"> + <c>enif_ioq_peek()</c></seealso></item> + <item><seealso marker="#enif_ioq_peek_head"> + <c>enif_ioq_peek_head()</c></seealso></item> + <item><seealso marker="#enif_inspect_iovec"> + <c>enif_inspect_iovec()</c></seealso></item> + <item><seealso marker="#enif_free_iovec"> + <c>enif_free_iovec()</c></seealso></item> + </list> + <p>Typical usage when writing to a file descriptor looks like this:</p> + <code type="none"><![CDATA[ +int writeiovec(ErlNifEnv *env, ERL_NIF_TERM term, ERL_NIF_TERM *tail, + ErlNifIOQueue *q, int fd) { + + ErlNifIOVec vec, *iovec = &vec; + SysIOVec *sysiovec; + int saved_errno; + int iovcnt, n; + + if (!enif_inspect_iovec(env, 64, term, tail, &iovec)) + return -2; + + if (enif_ioq_size(q) > 0) { + /* If the I/O queue contains data we enqueue the iovec and + then peek the data to write out of the queue. */ + if (!enif_ioq_enqv(q, iovec, 0)) + return -3; + + sysiovec = enif_ioq_peek(q, &iovcnt); + } else { + /* If the I/O queue is empty we skip the trip through it. */ + iovcnt = iovec->iovcnt; + sysiovec = iovec->iov; + } + + /* Attempt to write the data */ + n = writev(fd, sysiovec, iovcnt); + saved_errno = errno; + + if (enif_ioq_size(q) == 0) { + /* If the I/O queue was initially empty we enqueue any + remaining data into the queue for writing later. */ + if (n >= 0 && !enif_ioq_enqv(q, iovec, n)) + return -3; + } else { + /* Dequeue any data that was written from the queue. */ + if (n > 0 && !enif_ioq_deq(q, n, NULL)) + return -4; + } + + /* return n, which is either number of bytes written or -1 if + some error happened */ + errno = saved_errno; + return n; +}]]></code> + </item> <tag><marker id="lengthy_work"/>Long-running NIFs</tag> <item> <p>As mentioned in the <seealso marker="#WARNING">warning</seealso> text @@ -463,7 +540,7 @@ return term;</code> have to wait for a very long time. Blocking multi-scheduling, that is, calling <seealso marker="erlang#system_flag_multi_scheduling"> <c>erlang:system_flag(multi_scheduling, block)</c></seealso>, can - also take a very long time to complete. This becaue all ongoing + also take a very long time to complete. This is because all ongoing dirty operations on all dirty schedulers must complete before the block operation can complete.</p> <p>Many operations communicating with a process executing a @@ -513,7 +590,7 @@ return term;</code> <c>unload</c> is called to release the library. All are described individually below.</p> <p>The fourth argument <c>NULL</c> is ignored. It - was earlier used for the deprectated <c>reload</c> callback + was earlier used for the deprecated <c>reload</c> callback which is no longer supported since OTP 20.</p> <p>If compiling a NIF for static inclusion through <c>--enable-static-nifs</c>, you must define <c>STATIC_ERLANG_NIF</c> @@ -732,7 +809,7 @@ typedef void ErlNifResourceDtor(ErlNifEnv* env, void* obj);</code> <tag><marker id="ErlNifResourceDown"/><c>ErlNifResourceDown</c></tag> <item> <code type="none"> -typedef void ErlNifResourceDown(ErlNifEnv* env, void* obj, const ErlNifPid* pid, const ErlNifMonitor* mon);</code> +typedef void ErlNifResourceDown(ErlNifEnv* env, void* obj, ErlNifPid* pid, ErlNifMonitor* mon);</code> <p>The function prototype of a resource down function, called on the behalf of <seealso marker="#enif_monitor_process"> enif_monitor_process</seealso>. <c>obj</c> is the resource, <c>pid</c> @@ -798,7 +875,7 @@ typedef enum { <item> <p>An enumeration of the properties that can be requested from <seealso marker="#enif_make_unique_integer"> - <c>enif_unique_integer</c></seealso>. + <c>enif_make_unique_integer</c></seealso>. For default properties, use value <c>0</c>.</p> <taglist> <tag><c>ERL_NIF_UNIQUE_POSITIVE</c></tag> @@ -837,6 +914,36 @@ typedef enum { </item> </taglist> </item> + <tag><marker id="SysIOVec"/><c>SysIOVec</c></tag> + <item> + <p>A system I/O vector, as used by <c>writev</c> on + Unix and <c>WSASend</c> on Win32. It is used in + <c>ErlNifIOVec</c> and by + <seealso marker="#enif_ioq_peek"><c>enif_ioq_peek</c></seealso>.</p> + </item> + <tag><marker id="ErlNifIOVec"/><c>ErlNifIOVec</c></tag> + <item> + <code type="none"> +typedef struct { + int iovcnt; + size_t size; + SysIOVec* iov; +} ErlNifIOVec;</code> + <p>An I/O vector containing <c>iovcnt</c> <c>SysIOVec</c>s + pointing to the data. It is used by + <seealso marker="#enif_inspect_iovec"> + <c>enif_inspect_iovec</c></seealso> and + <seealso marker="#enif_ioq_enqv"> + <c>enif_ioq_enqv</c></seealso>.</p> + </item> + <tag><marker id="ErlNifIOQueueOpts"/><c>ErlNifIOQueueOpts</c></tag> + <item> + Options to configure a <c>ErlNifIOQueue</c>. + <taglist> + <tag>ERL_NIF_IOQ_NORMAL</tag> + <item><p>Create a normal I/O Queue</p></item> + </taglist> + </item> </taglist> </section> @@ -847,6 +954,8 @@ typedef enum { <desc> <p>Allocates memory of <c>size</c> bytes.</p> <p>Returns <c>NULL</c> if the allocation fails.</p> + <p>The returned pointer is suitably aligned for any built-in type that + fit in the allocated memory.</p> </desc> </func> @@ -865,6 +974,10 @@ typedef enum { <seealso marker="#enif_make_binary"><c>enif_make_binary</c></seealso>. An allocated (and owned) <c>ErlNifBinary</c> can be kept between NIF calls.</p> + <p>If you do not need to reallocate or keep the data alive across NIF + calls, consider using <seealso marker="#enif_make_new_binary"> + <c>enif_make_new_binary</c></seealso> instead as it will allocate + small binaries on the process heap when possible.</p> <p>Returns <c>true</c> on success, or <c>false</c> if allocation fails.</p> </desc> @@ -991,6 +1104,16 @@ typedef enum { </func> <func> + <name><ret>char*</ret> + <nametext>enif_cond_name(ErlNifCond* cnd)</nametext></name> + <fsummary></fsummary> + <desc> + <p>Same as <seealso marker="erl_driver#erl_drv_cond_name"> + <c>erl_drv_cond_name</c></seealso>.</p> + </desc> + </func> + + <func> <name><ret>void</ret> <nametext>enif_cond_signal(ErlNifCond *cnd)</nametext></name> <fsummary></fsummary> @@ -1123,6 +1246,19 @@ typedef enum { </func> <func> + <name><ret>int</ret><nametext>enif_fprintf(FILE *stream, const char *format, ...)</nametext></name> + <fsummary>Format strings and Erlang terms.</fsummary> + <desc> + <p>Similar to <c>fprintf</c> but this format string also accepts + <c>"%T"</c>, which formats Erlang terms of type + <seealso marker="#ERL_NIF_TERM"><c>ERL_NIF_TERM</c></seealso>.</p> + <p>This function is primarily intended for debugging purpose. It is not + recommended to print very large terms with <c>%T</c>. The function may + change <c>errno</c>, even if successful.</p> + </desc> + </func> + + <func> <name><ret>void</ret><nametext>enif_free(void* ptr)</nametext></name> <fsummary>Free dynamic memory.</fsummary> <desc> @@ -1143,6 +1279,31 @@ typedef enum { </func> <func> + <name><ret>void</ret> + <nametext>enif_free_iovec(ErlNifIOvec* iov)</nametext></name> + <fsummary>Free an ErlIOVec</fsummary> + <desc> + <p>Frees an io vector returned from + <seealso marker="#enif_inspect_iovec"> + <c>enif_inspect_iovec</c></seealso>. + This is needed only if a <c>NULL</c> environment is passed to + <seealso marker="#enif_inspect_iovec"> + <c>enif_inspect_iovec</c></seealso>.</p> + <code type="none"><![CDATA[ +ErlNifIOVec *iovec = NULL; +size_t max_elements = 128; +ERL_NIF_TERM tail; +if (!enif_inspect_iovec(NULL, max_elements, term, &tail, &iovec)) + return 0; + +// Do things with the iovec + +/* Free the iovector, possibly in another thread or nif function call */ +enif_free_iovec(iovec);]]></code> + </desc> + </func> + + <func> <name><ret>int</ret><nametext>enif_get_atom(ErlNifEnv* env, ERL_NIF_TERM term, char* buf, unsigned size, ErlNifCharEncoding encode)</nametext> </name> @@ -1449,6 +1610,141 @@ typedef enum { </func> <func> + <name><ret>int</ret><nametext>enif_inspect_iovec(ErlNifEnv* + env, size_t max_elements, ERL_NIF_TERM iovec_term, ERL_NIF_TERM* tail, + ErlNifIOVec** iovec)</nametext></name> + <fsummary>Inspect a list of binaries as an ErlNifIOVec.</fsummary> + <desc> + <p>Fills <c>iovec</c> with the list of binaries provided in + <c>iovec_term</c>. The number of elements handled in the call is + limited to <c>max_elements</c>, and <c>tail</c> is set to the + remainder of the list. Note that the output may be longer than + <c>max_elements</c> on some platforms. + </p> + <p>To create a list of binaries from an arbitrary iolist, use + <seealso marker="erts:erlang#iolist_to_iovec/1"> + <c>erlang:iolist_to_iovec/1</c></seealso>.</p> + <p>When calling this function, <c>iovec</c> should contain a pointer to + <c>NULL</c> or a ErlNifIOVec structure that should be used if + possible. e.g. + </p> + <code type="none"> +/* Don't use a pre-allocated structure */ +ErlNifIOVec *iovec = NULL; +enif_inspect_iovec(env, max_elements, term, &tail, &iovec); + +/* Use a stack-allocated vector as an optimization for vectors with few elements */ +ErlNifIOVec vec, *iovec = &vec; +enif_inspect_iovec(env, max_elements, term, &tail, &iovec); +</code> + <p>The contents of the <c>iovec</c> is valid until the called nif + function returns. If the <c>iovec</c> should be valid after the nif + call returns, it is possible to call this function with a + <c>NULL</c> environment. If no environment is given the <c>iovec</c> + owns the data in the vector and it has to be explicitly freed using + <seealso marker="#enif_free_iovec"><c>enif_free_iovec</c> + </seealso>.</p> + <p>Returns <c>true</c> on success, or <c>false</c> if <c>iovec_term</c> + not an iovec.</p> + </desc> + </func> + + <func> + <name><ret>ErlNifIOQueue *</ret> + <nametext>enif_ioq_create(ErlNifIOQueueOpts opts)</nametext></name> + <fsummary>Create a new IO Queue</fsummary> + <desc> + <p>Create a new I/O Queue that can be used to store data. + <c>opts</c> has to be set to <c>ERL_NIF_IOQ_NORMAL</c>. + </p> + </desc> + </func> + + <func> + <name><ret>void</ret> + <nametext>enif_ioq_destroy(ErlNifIOQueue *q)</nametext></name> + <fsummary>Destroy an IO Queue and free it's content</fsummary> + <desc> + <p>Destroy the I/O queue and free all of it's contents</p> + </desc> + </func> + + <func> + <name><ret>int</ret> + <nametext>enif_ioq_deq(ErlNifIOQueue *q, size_t count, size_t *size)</nametext></name> + <fsummary>Dequeue count bytes from the IO Queue</fsummary> + <desc> + <p>Dequeue <c>count</c> bytes from the I/O queue. + If <c>size</c> is not <c>NULL</c>, the new size of the queue + is placed there.</p> + <p>Returns <c>true</c> on success, or <c>false</c> if the I/O does + not contain <c>count</c> bytes. On failure the queue is left un-altered.</p> + </desc> + </func> + + <func> + <name><ret>int</ret> + <nametext>enif_ioq_enq_binary(ErlNifIOQueue *q, ErlNifBinary *bin, size_t skip)</nametext></name> + <fsummary>Enqueue the binary into the IO Queue</fsummary> + <desc> + <p>Enqueue the <c>bin</c> into <c>q</c> skipping the first <c>skip</c> bytes.</p> + <p>Returns <c>true</c> on success, or <c>false</c> if <c>skip</c> is greater + than the size of <c>bin</c>. Any ownership of the binary data is transferred + to the queue and <c>bin</c> is to be considered read-only for the rest of the NIF + call and then as released.</p> + </desc> + </func> + + <func> + <name><ret>int</ret> + <nametext>enif_ioq_enqv(ErlNifIOQueue *q, ErlNifIOVec *iovec, size_t skip)</nametext></name> + <fsummary>Enqueue the iovec into the IO Queue</fsummary> + <desc> + <p>Enqueue the <c>iovec</c> into <c>q</c> skipping the first <c>skip</c> bytes.</p> + <p>Returns <c>true</c> on success, or <c>false</c> if <c>skip</c> is greater + than the size of <c>iovec</c>.</p> + </desc> + </func> + + <func> + <name><ret>SysIOVec *</ret> + <nametext>enif_ioq_peek(ErlNifIOQueue *q, int *iovlen)</nametext></name> + <fsummary>Peek inside the IO Queue</fsummary> + <desc> + <p>Get the I/O queue as a pointer to an array of <c>SysIOVec</c>s. + It also returns the number of elements in <c>iovlen</c>.</p> + <p>Nothing is removed from the queue by this function, that must be done + with <seealso marker="#enif_ioq_deq"><c>enif_ioq_deq</c></seealso>.</p> + <p>The returned array is suitable to use with the Unix system + call <c>writev</c>.</p> + </desc> + </func> + + <func> + <name><ret>int</ret> + <nametext>enif_ioq_peek_head(ErlNifEnv *env, ErlNifIOQueue *q, size_t *size, ERL_NIF_TERM *bin_term)</nametext></name> + <fsummary>Peek the head of the IO Queue.</fsummary> + <desc> + <p>Get the head of the IO Queue as a binary term.</p> + <p>If <c>size</c> is not <c>NULL</c>, the size of the head is placed + there.</p> + <p>Nothing is removed from the queue by this function, that must be done + with <seealso marker="#enif_ioq_deq"><c>enif_ioq_deq</c></seealso>.</p> + <p>Returns <c>true</c> on success, or <c>false</c> if the queue is + empty.</p> + </desc> + </func> + + <func> + <name><ret>size_t</ret> + <nametext>enif_ioq_size(ErlNifIOQueue *q)</nametext></name> + <fsummary>Get the current size of the IO Queue</fsummary> + <desc> + <p>Get the size of <c>q</c>.</p> + </desc> + </func> + + <func> <name><ret>int</ret> <nametext>enif_is_atom(ErlNifEnv* env, ERL_NIF_TERM term)</nametext> </name> @@ -1890,6 +2186,20 @@ typedef enum { </func> <func> + <name><ret>int</ret> + <nametext>enif_make_map_from_arrays(ErlNifEnv* env, ERL_NIF_TERM keys[], + ERL_NIF_TERM values[], size_t cnt, ERL_NIF_TERM *map_out)</nametext></name> + <fsummary>Make map term from the given keys and values.</fsummary> + <desc> + <p>Makes a map term from the given keys and values.</p> + <p>If successful, this function sets <c>*map_out</c> to the new map and + returns <c>true</c>. Returns <c>false</c> there are any duplicate + keys.</p> + <p>All keys and values must belong to <c>env</c>.</p> + </desc> + </func> + + <func> <name><ret>unsigned char *</ret><nametext>enif_make_new_binary(ErlNifEnv* env, size_t size, ERL_NIF_TERM* termp)</nametext></name> <fsummary>Allocate and create a new binary term.</fsummary> @@ -1952,10 +2262,33 @@ typedef enum { details, see the <seealso marker="#enif_resource_example">example of creating and returning a resource object</seealso> in the User's Guide.</p> - <p>Notice that the only defined behavior of using a resource term in - an Erlang program is to store it and send it between processes on the - same node. Other operations, such as matching or - <c>term_to_binary</c>, have unpredictable (but harmless) results.</p> + <note> + <p>Since ERTS 9.0 (OTP-20.0), resource terms have a defined behavior + when compared and serialized through <c>term_to_binary</c> or passed + between nodes.</p> + <list type="bulleted"> + <item> + <p>Two resource terms will compare equal iff they + would yield the same resource object pointer when passed to + <seealso marker="#enif_get_resource"><c>enif_get_resource</c></seealso>.</p> + </item> + <item> + <p>A resource term can be serialized with <c>term_to_binary</c> and later + be fully recreated if the resource object is still alive when + <c>binary_to_term</c> is called. A <em>stale</em> resource term will be + returned from <c>binary_to_term</c> if the resource object has + been deallocated. <seealso marker="#enif_get_resource"><c>enif_get_resource</c></seealso> + will return false for stale resource terms.</p> + <p>The same principles of serialization apply when passing + resource terms in messages to remote nodes and back again. A + resource term will act stale on all nodes except the node where + its resource object is still alive in memory.</p> + </item> + </list> + <p>Before ERTS 9.0 (OTP-20.0), all resource terms did + compare equal to each other and to empty binaries (<c><<>></c>). + If serialized, they would be recreated as plain empty binaries.</p> + </note> </desc> </func> @@ -2320,6 +2653,16 @@ enif_map_iterator_destroy(env, &iter);</code> </func> <func> + <name><ret>char*</ret> + <nametext>enif_mutex_name(ErlNifMutex* mtx)</nametext></name> + <fsummary></fsummary> + <desc> + <p>Same as <seealso marker="erl_driver#erl_drv_mutex_name"> + <c>erl_drv_mutex_name</c></seealso>.</p> + </desc> + </func> + + <func> <name><ret>int</ret> <nametext>enif_mutex_trylock(ErlNifMutex *mtx)</nametext></name> <fsummary></fsummary> @@ -2486,6 +2829,20 @@ enif_map_iterator_destroy(env, &iter);</code> </func> <func> + <name><ret>void *</ret> + <nametext>enif_realloc(void* ptr, size_t size)</nametext></name> + <fsummary>Reallocate dynamic memory.</fsummary> + <desc> + <p>Reallocates memory allocated by + <seealso marker="#enif_alloc"><c>enif_alloc</c></seealso> to + <c>size</c> bytes.</p> + <p>Returns <c>NULL</c> if the reallocation fails.</p> + <p>The returned pointer is suitably aligned for any built-in type that + fit in the allocated memory.</p> + </desc> + </func> + + <func> <name><ret>int</ret> <nametext>enif_realloc_binary(ErlNifBinary* bin, size_t size)</nametext> </name> @@ -2550,6 +2907,16 @@ enif_map_iterator_destroy(env, &iter);</code> </func> <func> + <name><ret>char*</ret> + <nametext>enif_rwlock_name(ErlNifRWLock* rwlck)</nametext></name> + <fsummary></fsummary> + <desc> + <p>Same as <seealso marker="erl_driver#erl_drv_rwlock_name"> + <c>erl_drv_rwlock_name</c></seealso>.</p> + </desc> + </func> + + <func> <name><ret>void</ret> <nametext>enif_rwlock_rlock(ErlNifRWLock *rwlck)</nametext></name> <fsummary></fsummary> @@ -2670,7 +3037,7 @@ enif_map_iterator_destroy(env, &iter);</code> <p>Argument <c>mode</c> describes the type of events to wait for. It can be <c>ERL_NIF_SELECT_READ</c>, <c>ERL_NIF_SELECT_WRITE</c> or a bitwise OR combination to wait for both. It can also be <c>ERL_NIF_SELECT_STOP</c> - which is described further below. When a read or write event is triggerred, + which is described further below. When a read or write event is triggered, a notification message like this is sent to the process identified by <c>pid</c>:</p> <code type="none">{select, Obj, Ref, ready_input | ready_output}</code> @@ -2721,7 +3088,7 @@ enif_map_iterator_destroy(env, &iter);</code> <item>The stop callback was scheduled to run on some other thread or later by this thread.</item> </taglist> - <p>Returns a negative value if the call failed where the follwing bits can be set:</p> + <p>Returns a negative value if the call failed where the following bits can be set:</p> <taglist> <tag><c>ERL_NIF_SELECT_INVALID_EVENT</c></tag> <item>Argument <c>event</c> is not a valid OS event object.</item> @@ -2729,9 +3096,9 @@ enif_map_iterator_destroy(env, &iter);</code> <item>The system call failed to add the event object to the poll set.</item> </taglist> <note> - <p>Use bitwise AND to test for specific bits in the return vaue. + <p>Use bitwise AND to test for specific bits in the return value. New significant bits may be added in future releases to give more detailed - information for both failed and successful calls. Do NOT use equallity tests + information for both failed and successful calls. Do NOT use equality tests like <c>==</c>, as that may cause your application to stop working.</p> <p>Example:</p> <code type="none"> @@ -2754,9 +3121,10 @@ if (retval & ERL_NIF_SELECT_STOP_CALLED) { </name> <fsummary>Get the pid of the calling process.</fsummary> <desc> - <p>Initializes the pid variable <c>*pid</c> to represent the - calling process.</p> - <p>Returns <c>pid</c>.</p> + <p>Initializes the <seealso marker="#ErlNifPid"><c>ErlNifPid</c></seealso> + variable at <c>*pid</c> to represent the calling process.</p> + <p>Returns <c>pid</c> if successful, or NULL if <c>caller_env</c> is not + a <seealso marker="#ErlNifEnv">process-bound environment</seealso>.</p> </desc> </func> @@ -2795,7 +3163,7 @@ if (retval & ERL_NIF_SELECT_STOP_CALLED) { <c>enif_free_env</c></seealso> of cleared for reuse with <seealso marker="#enif_clear_env"><c>enif_clear_env</c></seealso>.</p> <p>If <c>msg_env</c> is set to <c>NULL</c>, the <c>msg</c> term is - copied and the original term and its environemt is still valid after + copied and the original term and its environment 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 @@ -2824,7 +3192,11 @@ if (retval & ERL_NIF_SELECT_STOP_CALLED) { <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> + <c>"%T"</c>, which formats Erlang terms of type + <seealso marker="#ERL_NIF_TERM"><c>ERL_NIF_TERM</c></seealso>.</p> + <p>This function is primarily intended for debugging purpose. It is not + recommended to print very large terms with <c>%T</c>. The function may + change <c>errno</c>, even if successful.</p> </desc> </func> @@ -2888,6 +3260,16 @@ if (retval & ERL_NIF_SELECT_STOP_CALLED) { </func> <func> + <name><ret>char*</ret> + <nametext>enif_thread_name(ErlNifTid tid)</nametext></name> + <fsummary>Thread name</fsummary> + <desc> + <p>Same as <seealso marker="erl_driver#erl_drv_thread_name"> + <c>erl_drv_thread_name</c></seealso>.</p> + </desc> + </func> + + <func> <name><ret>ErlNifThreadOpts *</ret> <nametext>enif_thread_opts_create(char *name)</nametext></name> <fsummary></fsummary> @@ -3005,6 +3387,30 @@ if (retval & ERL_NIF_SELECT_STOP_CALLED) { <func> <name><ret>int</ret> + <nametext>enif_vfprintf(FILE *stream, const char *format, va_list ap) + </nametext></name> + <fsummary>Format strings and Erlang terms.</fsummary> + <desc> + <p>Equivalent to <seealso marker="#enif_fprintf"><c>enif_fprintf</c></seealso> + except that its called with a <c>va_list</c> instead of a variable number of + arguments.</p> + </desc> + </func> + + <func> + <name><ret>int</ret> + <nametext>enif_vsnprintf(char *str, size_t size, const char *format, va_list ap) + </nametext></name> + <fsummary>Format strings and Erlang terms.</fsummary> + <desc> + <p>Equivalent to <seealso marker="#enif_snprintf"><c>enif_snprintf</c></seealso> + except that its called with a <c>va_list</c> instead of a variable number of + arguments.</p> + </desc> + </func> + + <func> + <name><ret>int</ret> <nametext>enif_whereis_pid(ErlNifEnv *env, ERL_NIF_TERM name, ErlNifPid *pid)</nametext></name> <fsummary>Looks up a process by its registered name.</fsummary> |