From: Eero Saynatkari <ruby-ml@...>
Date: 2005-11-08T18:43:13+09:00
Subject: Re: crash of extension on rb_str_new2

Eero Saynatkari wrote:
> newbie wrote:
> 
>> Hi, all
>> I am integrating a 3rd party API with ruby extension. The code is
>> roughly like this
>> void my_function()
>> {
>>         char p[256];
>>     ...//assign the value of p in the api
>>
>>     return rb_str_new2(p);//This cause a crash.
>> }
>> while if I change the last part a little bit as,
>>     VALUE str=rb_str_new2(p);
>>     return str;
>> This seems not crashing
>>
>> It looks like more related to ruby GC? Can anyone explain on this? and
>> how to prevent this kind of crash?
> 
> 
> p is a pointer to a local array which may be causing
> the problem since the memory is released when you exit
> the function's scope. You should probably be malloc()ing
> the original string to char* p instead just in general
> C programming terms.
> 
> That said, I am not quite sure why the second version
> would work if that were the underlying cause here.

Bah, too little C lately. The function's return type should be
VALUE, not void (if you have this in your actual code).

Warning about the local array still stands :)

>> Thanks!

E