Re: how to use lmem.h ?

[Bertrand Mansion <lua@...>]

On Sat, Feb 21, 2009 at 3:47 PM, Jerome Vuarand
<jerome.vuarand@gmail.com> wrote:
> 2009/2/21 Bertrand Mansion <lua@mamasam.net>:
>> I am trying to create a C module for Lua. One of the functions deals
>> with string quoting so I need to allocate a buffer with 2 times +1 the
>> memory occupied by the source string. Usually, I would use malloc()
>> but I noticed that there is a lmem.h file with a luaM_malloc()
>> function, so I could write something like this:
>>  to = luaM_malloc(L, 2 * size);
>>
>> Unfortunately, #include "lmem.h" doesn't work if I install Lua using
>> the default Makefile (I am on Macosx). Is there a way to build Lua or
>> some extra steps I should do manually in order to be able to use
>> "lmem.h" ? Thanks,
>
> You have two normal ways to allocate memory with Lua. You can either
> call lua_getallocf to retrieve Lua's memory allocator and use it. You
> can also create a userdata on the stack with lua_newuserdata. The
> interesting aspect of using a userdata is that it is garbage
> collected, and you don't have to take care of de-allocation, even in
> the case of Lua errors.

Thanks Jérome, but here is my code:

    size_t slen, dlen;
    const char *src = luaL_checklstring(L, 1, &slen);
    char *buf;

    slen = luaL_optlong(L, 2, slen);
    buf = (char*)malloc(2 * slen);
    dlen = apreq_quote(buf, src, slen);
    lua_pushlstring(L, buf, dlen);
    free(buf);
    return 1;

How would I then use lua_getallocf instead of malloc/free ?
(I tried but got a segfault)

-- 
Bertrand Mansion
Mamasam