Re: Making a modifiable copy of a string in C

[Gé Weijers <ge@...>]

On Sun, Apr 7, 2019 at 4:05 AM Marc Balmer <marc@msys.ch> wrote:

So far I came up with two different ways:

First variant:

        const char *s;
        char *u;

        s = luaL_checklstring(L, 2, &len);
        u = lua_newuserdata(L, len);
        memcpy(u, s, len);

If you plan to pass a string to C string routines you have to copy the null character.

u = lua_newuserdata(L, len+1);

memcpy(u, s, len+1);

I assume the Lua string does not contain any null characters, or the C routines will stop processing in the middle of a Lua string. If you want to process null characters as part of strings you may have to write your own code.

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Gé