[erlang-questions] [Erlang][Request] Invoke C funtion in Erlang

Gleb Peregud gleber.p@REDACTED
Wed Dec 14 14:23:16 CET 2011

2011/12/14 郎咸武 <langxianzhe@REDACTED>:
> Thanks Gleb Peregud.
> Your are right. But a new request is come on. I input list [1,7,0,9] as
> parameter. Ii only return [1,7]. The [0,9] is lose. Maybe the '0' elment as
> a NUL in C.
> What  should i do .
> Thanks
> 8>complex6:get_name([1,7,0,9]).
> [1,7]
> 9>

Most probably enif_get_string does copy all four bytes to the buffer,
but enif_make_string treats NUL as termination mark of a string. Try
using enif_make_string_len instead.

On the other side it looks like you are interested in a binary-like
data, instead of a string-like data. You can make use of the following

ErlNifBinary input;
if(!enif_inspect_iolist_as_binary(env, argv[0], &input)) {
 return enif_make_badarg(env);

As the result of this:
input.data - will contain pointer to a memory, where all bytes from
argument are stored
input.size - size of that memory area

Also it's worth noting that this will work for both lists (with
integers less than 256) and binaries, and for any nested combinations
of them.

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