CODEWITHSUNDEEP
cdlllua
Arthur Bouvier
Arthur Bouvier

Reputation: 99

Lua segfault when loading dll

I'm trying to make a c extension dll for lua. I have this csin.c:

#include <lua.h>
#include <lauxlib.h>
#include <lualib.h>
#include <math.h>

static int l_sin(lua_State *L) {
    double d = lua_tonumber(L, 1);
    lua_pushnumber(L, sin(d));
    return 1;
}

int luaopen_csin(lua_State *L) {
    lua_register(L, "csin", l_sin);
    return 0;
}

I'm compiling it with gcc -Wall -shared -Ilua-5.3.3/include -Llua-5.3.3/lib csin.c -o csin.dll -llua. The include dir just has the .h files from the Lua 5.3.3 src download and the lib dir has liblua.a which I compiled with make generic. It compiles without error, but when I try to use it in a Lua script, it just gives a Segmentation Fault.

Here is lcsin.lua:

require("csin")
print(csin(45))

I just run it with lua lcsin.lua, lua being a link to lua32/lua53.exe, which I think I got from Lua's binary downloads. I tried using the compiled lua-5.3.3/src/lua.exe too, but it says:

lua-5.3.3/src/lua: lcsin.lua:1: module 'csin' not found:
        no field package.preload['csin']
        no file '/usr/local/share/lua/5.3/csin.lua'
        no file '/usr/local/share/lua/5.3/csin/init.lua'
        no file '/usr/local/lib/lua/5.3/csin.lua'
        no file '/usr/local/lib/lua/5.3/csin/init.lua'
        no file './csin.lua'
        no file './csin/init.lua'
        no file '/usr/local/lib/lua/5.3/csin.so'
        no file '/usr/local/lib/lua/5.3/loadall.so'
        no file './csin.so'
stack traceback:
        [C]: in function 'require'
        lcsin.lua:1: in main chunk
        [C]: in ?

I think that error is because the compiled one isn't looking for .dll files but .so files. I'm using cygwin. Windows/Linux inconsistencies have been a pain in the *** for a while now. I've tried example code online, and nothing works.

Upvotes: 2

Views: 483

Answers (1)

Paul Kulchenko
Paul Kulchenko

Reputation: 26744

If the issue is indeed with searching for .so files instead of *.dll files, it should be easy to fix by adding the appropriate pattern to package.cpath: 

package.cpath = package.cpath..";./?.dll"
require("csin")

Assuming csin.dll is in the current folder, it should be able to find and load it.

Upvotes: 2

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