From: Christian Kaiser <bchk@...>
Date: 2004-05-28T22:02:10+09:00
Subject: Re: Calling a c function from ruby?

Well in C you only get VALUE.

To get a char*, you use rb_str2cstr() to get the string and its length:

myfunc(VALUE v)
{
    char*    pc = rb_str2cstr(v,NULL);
}

To get a char*[], you need to walk the array (passed in VALUE) and get the
strings using the above function. I guess using rb_ary_each(), you can walk
the array.

To get a BYTE*, you also use rb_str2cstr() - remember, a string may contain
any character, including '\0':

myfunc(VALUE v)
{
    long    len;
    BYTE*   data = rb_str2cstr(v,&len);
}


(There are newer APIs like StringValue() and StringValuePtr(), you might
check those also...)

Christian

"Randy Lawrence" <jm@zzzzzzzzzzzz.com> schrieb im Newsbeitrag
news:F_ztc.15523$eH1.6931874@newssvr28.news.prodigy.com...
> I'm having trouble calling a c function from ruby and haven't been able
> to find a solution using google.
>
> Specifically, I'd like to call functions that receive these three
datatypes:
>
> char*
> char*[]
> byte[]
>
> Swig 1.3 has been great in helping me call a c++ function that uses a
> std::string parameter but the 3 c datatypes mentioned above are eluding
me.
>
> Thanks.