Re: FFI newby question: importing C functions
- From: QuentinC <webmaster@xxxxxxxxxxxx>
- To: luajit@xxxxxxxxxxxxx
- Date: Tue, 26 Jun 2012 00:20:55 +0200
> The round() function is only in the C99 standard, but not in C89.
MinGW links against MSVCRT, which is not C99-compliant.
In that case, why can I use it without any problem in my C code ? It is
also correctly defined in stdlib.h.
A classic wrapper like this one would perfectly work :
int round2 (lua_State* l) {
lua_pushnumber(l, round(luaL_checknumber(l,1)));
return 1;
}
But as I observed, FFI calls are much faster compared to wrapped
functions in many cases (and you don't have to bother with trivial
wrappers), so I though it was better to use FFI.
moreover, I don't know for luajit itself (I used allmost the default
makefile without any change), but my program is actually compiled with
the flag -std=gnu99, so I'm normally in C99 mode.
Thank you for the pure lua replacement. It's definitely better to use
it, for something so simple.
Nonetheless, I'm anyway curious to know why I can access it in native C
code without any problem but not in lua FFI. It's not impossible that I
get this problem again with another function later, for which there
wouldn't be a so simple pure lua replacement.
Thank you.
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