erl_nif

Allocate memory of size bytes. Return NULL if allocation failed.

Allocate a new binary of size size bytes. Initialize the structure pointed to by bin to refer to the allocated binary. The binary must either be released by enif_release_binary or ownership transferred to an Erlang term with enif_make_binary. An allocated (and owned) ErlNifBinary can be kept between NIF calls.

Return true on success or false if allocation failed.

Allocate a new process independent environment. The environment can be used to hold terms that is not bound to any process. Such terms can later be copied to a process environment with enif_make_copy or be sent to a process as a message with enif_send.

Return pointer to the new environment.

Allocate a memory managed resource object of type type and size size bytes.

Free all terms in an environment and clear it for reuse. The environment must have been allocated with enif_alloc_env.

Return an integer less than, equal to, or greater than zero if lhs is found, respectively, to be less than, equal, or greater than rhs. Corresponds to the Erlang operators ==, /=, =<, <, >= and > (but not =:= or =/=).

Same as erl_drv_cond_broadcast.

Same as erl_drv_cond_create.

Same as erl_drv_cond_destroy.

Same as erl_drv_cond_signal.

Same as erl_drv_cond_wait.

Give the runtime system a hint about how much CPU time the current NIF call has consumed since last hint, or since the start of the NIF if no previous hint has been given. The time is given as a percent of the timeslice that a process is allowed to execute Erlang code until it may be suspended to give time for other runnable processes. The scheduling timeslice is not an exact entity, but can usually be approximated to about 1 millisecond.

Note that it is up to the runtime system to determine if and how to use this information. Implementations on some platforms may use other means in order to determine consumed CPU time. Lengthy NIFs should regardless of this frequently call enif_consume_timeslice in order to determine if it is allowed to continue execution or not.

Returns 1 if the timeslice is exhausted, or 0 otherwise. If 1 is returned the NIF should return as soon as possible in order for the process to yield.

Argument percent must be an integer between 1 and 100. This function must only be called from a NIF-calling thread and argument env must be the environment of the calling process.

This function is provided to better support co-operative scheduling, improve system responsiveness, and make it easier to prevent misbehaviors of the VM due to a NIF monopolizing a scheduler thread. It can be used to divide length work into a number of repeated NIF-calls without the need to create threads. See also the warning text at the beginning of this document.

Same as erl_drv_equal_tids.

Free memory allocated by enif_alloc.

Free an environment allocated with enif_alloc_env. All terms created in the environment will be freed as well.

Write a null-terminated string, in the buffer pointed to by buf of size size, consisting of the string representation of the atom term with encoding encode. Return the number of bytes written (including terminating null character) or 0 if term is not an atom with maximum length of size-1.

Set *len to the length (number of bytes excluding terminating null character) of the atom term with encoding encode. Return true on success or false if term is not an atom.

Set *dp to the floating point value of term. Return true on success or false if term is not a float.

Set *ip to the integer value of term. Return true on success or false if term is not an integer or is outside the bounds of type int.

Set *ip to the integer value of term. Return true on success or false if term is not an integer or is outside the bounds of a signed 64-bit integer.

If term is the pid of a node local process, initialize the pid variable *pid from it and return true. Otherwise return false. No check if the process is alive is done.

Set *head and *tail from list and return true, or return false if list is not a non-empty list.

Set *len to the length of list term and return true, or return false if term is not a list.

Set *ip to the long integer value of term and return true, or return false if term is not an integer or is outside the bounds of type long int.

Set *objp to point to the resource object referred to by term.

Return true on success or false if term is not a handle to a resource object of type type.

Write a null-terminated string, in the buffer pointed to by buf with size size, consisting of the characters in the string list. The characters are written using encoding encode. Return the number of bytes written (including terminating null character), or -size if the string was truncated due to buffer space, or 0 if list is not a string that can be encoded with encode or if size was less than 1. The written string is always null-terminated unless buffer size is less than 1.

If term is a tuple, set *array to point to an array containing the elements of the tuple and set *arity to the number of elements. Note that the array is read-only and (*array)[N-1] will be the Nth element of the tuple. *array is undefined if the arity of the tuple is zero.

Return true on success or false if term is not a tuple.

Set *ip to the unsigned integer value of term and return true, or return false if term is not an unsigned integer or is outside the bounds of type unsigned int.

Set *ip to the unsigned integer value of term and return true, or return false if term is not an unsigned integer or is outside the bounds of an unsigned 64-bit integer.

Set *ip to the unsigned long integer value of term and return true, or return false if term is not an unsigned integer or is outside the bounds of type unsigned long.

Initialize the structure pointed to by bin with information about the binary term bin_term. Return true on success or false if bin_term is not a binary.

Initialize the structure pointed to by bin with one continuous buffer with the same byte content as iolist. As with inspect_binary, the data pointed to by bin is transient and does not need to be released. Return true on success or false if iolist is not an iolist.

Return true if term is an atom.

Return true if term is a binary

Return true if term is an empty list.

Return true if term is an exception.

Return true if term is a number.

Return true if term is a fun.

Return true if the two terms are identical. Corresponds to the Erlang operators =:= and =/=.

Check to see if the current NIF is executing on a dirty scheduler thread. If the emulator is built with threading support, calling enif_is_on_dirty_scheduler from within a dirty NIF returns true. It returns false when the calling NIF is a regular NIF running on a normal scheduler thread, or when the emulator is built without threading support.

Return true if term is a pid.

Return true if term is a port.

Return true if term is a reference.

Return true if term is a tuple.

Return true if term is a list.

Add a reference to resource object obj obtained from enif_alloc_resource. Each call to enif_keep_resource for an object must be balanced by a call to enif_release_resource before the object will be destructed.

Create an atom term from the null-terminated C-string name with iso-latin-1 encoding.

Create an atom term from the string name with length len. Null-characters are treated as any other characters.

Make a badarg exception to be returned from a NIF, and set an associated exception reason in env. If enif_make_badarg is called, the term it returns must be returned from the function that called it. No other return value is allowed. Also, the term returned from enif_make_badarg may be passed only to enif_is_exception and not to any other NIF API function.

Make a binary term from bin. Any ownership of the binary data will be transferred to the created term and bin should be considered read-only for the rest of the NIF call and then as released.

Make a copy of term src_term. The copy will be created in environment dst_env. The source term may be located in any environment.

Create a floating-point term from a double.

Try to create the term of an already existing atom from the null-terminated C-string name with encoding encode. If the atom already exists store the term in *atom and return true, otherwise return false.

Try to create the term of an already existing atom from the string name with length len and encoding encode. Null-characters are treated as any other characters. If the atom already exists store the term in *atom and return true, otherwise return false.

Create an integer term.

Create an integer term from a signed 64-bit integer.

Create an ordinary list term of length cnt. Expects cnt number of arguments (after cnt) of type ERL_NIF_TERM as the elements of the list. An empty list is returned if cnt is 0.

Create an ordinary list term with length indicated by the function name. Prefer these functions (macros) over the variadic enif_make_list to get a compile time error if the number of arguments does not match.

Create a list cell [head | tail].

Create an ordinary list containing the elements of array arr of length cnt. An empty list is returned if cnt is 0.

Set *list to the reverse list of the list term and return true, or return false if term 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.

Create an integer term from a long int.

Allocate a binary of size size bytes and create an owning term. The binary data is mutable until the calling NIF returns. This is a quick way to create a new binary without having to use ErlNifBinary. The drawbacks are that the binary can not be kept between NIF calls and it can not be reallocated.

Return a pointer to the raw binary data and set *termp to the binary term.

Make a pid term from *pid.

Create a reference like erlang:make_ref/0.

Create an opaque handle to a memory managed resource object obtained by enif_alloc_resource. No ownership transfer is done, as the resource object still needs to be released by enif_release_resource, but note that the call to enif_release_resource can occur immediately after obtaining the term from enif_make_resource, in which case the resource object will be deallocated when the term is garbage collected. See the example of creating and returning a resource object for more details.

Note that the only defined behaviour 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 term_to_binary will have unpredictable (but harmless) results.

Create a binary term that is memory managed by a resource object obj obtained by enif_alloc_resource. The returned binary term will consist of size bytes pointed to by data. This raw binary data must be kept readable and unchanged until the destructor of the resource is called. The binary data may be stored external to the resource object in which case it is the responsibility of the destructor to release the data.

Several binary terms may be managed by the same resource object. The destructor will not be called until the last binary is garbage collected. This can be useful as a way to return different parts of a larger binary buffer.

As with enif_make_resource, no ownership transfer is done. The resource still needs to be released with enif_release_resource.

Create a list containing the characters of the null-terminated string string with encoding encoding.

Create a list containing the characters of the string string with length len and encoding encoding. Null-characters are treated as any other characters.

Make a subbinary of binary bin_term, starting at zero-based position pos with a length of size bytes. bin_term must be a binary or bitstring and pos+size must be less or equal to the number of whole bytes in bin_term.

Create a tuple term of arity cnt. Expects cnt number of arguments (after cnt) of type ERL_NIF_TERM as the elements of the tuple.

Create a tuple term with length indicated by the function name. Prefer these functions (macros) over the variadic enif_make_tuple to get a compile time error if the number of arguments does not match.

Create a tuple containing the elements of array arr of length cnt.

Create an integer term from an unsigned int.

Create an integer term from an unsigned 64-bit integer.

Create an integer term from an unsigned long int.

Same as erl_drv_mutex_create.

Same as erl_drv_mutex_destroy.

Same as erl_drv_mutex_lock.

Same as erl_drv_mutex_trylock.

Same as erl_drv_mutex_unlock.

Create or takeover a resource type identified by the string name and give it the destructor function pointed to by dtor. Argument flags can have the following values:

The two flag values can be combined with bitwise-or. The name of the resource type is local to the calling module. Argument module_str is not (yet) used and must be NULL. The dtor may be NULL in case no destructor is needed.

On success, return a pointer to the resource type and *tried will be set to either ERL_NIF_RT_CREATE or ERL_NIF_RT_TAKEOVER to indicate what was actually done. On failure, return NULL and set *tried to flags. It is allowed to set tried to NULL.

Note that enif_open_resource_type is only allowed to be called in the three callbacks load, reload and upgrade.

Return the pointer to the private data that was set by load, reload or upgrade.

Was previously named enif_get_data.

Change the size of a binary bin. The source binary may be read-only, in which case it will be left untouched and a mutable copy is allocated and assigned to *bin. Return true on success, false if memory allocation failed.

Release a binary obtained from enif_alloc_binary.

Remove a reference to resource object objobtained from enif_alloc_resource. The resource object will be destructed when the last reference is removed. Each call to enif_release_resource must correspond to a previous call to enif_alloc_resource or enif_keep_resource. References made by enif_make_resource can only be removed by the garbage collector.

Same as erl_drv_rwlock_create.

Same as erl_drv_rwlock_destroy.

Same as erl_drv_rwlock_rlock.

Same as erl_drv_rwlock_runlock.

Same as erl_drv_rwlock_rwlock.

Same as erl_drv_rwlock_rwunlock.

Same as erl_drv_rwlock_tryrlock.

Same as erl_drv_rwlock_tryrwlock.

Schedule NIF fp to execute. This function allows an application to break up long-running work into multiple regular NIF calls or to schedule a dirty NIF to execute on a dirty scheduler thread (note that the dirty NIF functionality described here is experimental and that you have to enable support for dirty schedulers when building OTP in order to try the functionality out).

The fun_name argument provides a name for the NIF being scheduled for execution. If it cannot be converted to an atom, enif_schedule_nif returns a badarg exception.

The flags argument must be set to 0 for a regular NIF, or if the emulator was built the experimental dirty scheduler support enabled, flags can be set to either ERL_NIF_DIRTY_JOB_CPU_BOUND if the job is expected to be primarily CPU-bound, or ERL_NIF_DIRTY_JOB_IO_BOUND 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 badarg exception.

The argc and argv arguments can either be the originals passed into the calling NIF, or they can be values created by the calling NIF.

The calling NIF must use the return value of enif_schedule_nif as its own return value.

Be aware that enif_schedule_nif, 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.

Initialize the pid variable *pid to represent the calling process. Return pid.

Send a message to a process.

Return true on success, or false if *to_pid does not refer to an alive local process.

The message environment msg_env with all its terms (including msg) will be invalidated by a successful call to enif_send. The environment should either be freed with enif_free_env of cleared for reuse with enif_clear_env.

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.

Get the byte size of a resource object obj obtained by enif_alloc_resource.

Same as driver_system_info.

Same as erl_drv_thread_create.

Same as erl_drv_thread_exit.

Same as erl_drv_thread_join .

Same as erl_drv_thread_opts_create.

Same as erl_drv_thread_opts_destroy.

Same as erl_drv_thread_self.

Same as erl_drv_tsd_key_create.

Same as erl_drv_tsd_key_destroy.

Same as erl_drv_tsd_get.

Same as erl_drv_tsd_set.