erl_malloc

(erl_interface) Memory allocation functions.

Note!

The support for VxWorks is deprecated as of OTP 22, and will be removed in OTP 23.

Note!

The old legacy erl_interface library (functions with prefix erl_) is deprecated as of OTP 22, and will be removed in OTP 23. This does not apply to the ei library. Reasonably new gcc compilers will issue deprecation warnings. In order to disable these warnings, define the macro EI_NO_DEPR_WARN.

This module provides functions for allocating and deallocating memory.

Functions

ETERM *erl_alloc_eterm(etype)
  • unsigned char etype;

Allocates an (ETERM) structure.

Specify etype as one of the following constants:

ERL_INTEGER ERL_U_INTEGER (unsigned integer) ERL_ATOM ERL_PID (Erlang process identifier) ERL_PORT ERL_REF (Erlang reference) ERL_LIST ERL_EMPTY_LIST ERL_TUPLE ERL_BINARY ERL_FLOAT ERL_VARIABLE ERL_SMALL_BIG (bignum) ERL_U_SMALL_BIG (bignum)

ERL_SMALL_BIG and ERL_U_SMALL_BIG are for creating Erlang bignums, which can contain integers of any size. The size of an integer in Erlang is machine-dependent, but any integer > 2^28 requires a bignum.

voiderl_eterm_release(void)

Clears the freelist, where blocks are placed when they are released by erl_free_term() and erl_free_compound().

voiderl_eterm_statistics(allocated, freed)
  • long *allocated;
  • long *freed;

Reports term allocation statistics.

allocated and freed are initialized to contain information about the fix-allocator used to allocate ETERM components.

allocated is the number of blocks currently allocated to ETERM objects.

freed is the length of the freelist, where blocks are placed when they are released by erl_free_term() and erl_free_compound().
voiderl_free(ptr)
  • void *ptr;

Calls the standard free() function.

voiderl_free_array(array, size)
  • ETERM **array;
  • int size;

Frees an array of Erlang terms.

array is an array of ETERM* objects. size is the number of terms in the array.
voiderl_free_compound(t)
  • ETERM *t;

Normally it is the programmer's responsibility to free each Erlang term that has been returned from any of the Erl_Interface functions. However, as many of the functions that build new Erlang terms in fact share objects with other existing terms, it can be difficult for the programmer to maintain pointers to all such terms to free them individually.

erl_free_compound() recursively frees all of the subterms associated with a specified Erlang term, regardless of whether we are still holding pointers to the subterms.

For an example, see section Building Terms and Patterns in the User's Guide.

voiderl_free_term(t)
  • ETERM *t;

Frees an Erlang term.

voiderl_malloc(size)
  • long size;

Calls the standard malloc() function.