text: /*
  ** $Id: loadlib.c,v 1.130 2017/01/12 17:14:26 roberto Exp $
  ** Dynamic library loader for Lua
  ** See Copyright Notice in lua.h
  **
  ** This module contains an implementation of loadlib for Unix systems
  ** that have dlfcn, an implementation for Windows, and a stub for other
  ** systems.
  */
  
  #define loadlib_c
  #define LUA_LIB
  
  #include "lprefix.h"
  
  
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  
  #include "lua.h"
  
  #include "lauxlib.h"
  #include "lualib.h"
  
  
  /*
  ** LUA_IGMARK is a mark to ignore all before it when building the
  ** luaopen_ function name.
  */
  #if !defined (LUA_IGMARK)
  #define LUA_IGMARK		"-"
  #endif
  
  
  /*
  ** LUA_CSUBSEP is the character that replaces dots in submodule names
  ** when searching for a C loader.
  ** LUA_LSUBSEP is the character that replaces dots in submodule names
  ** when searching for a Lua loader.
  */
  #if !defined(LUA_CSUBSEP)
  #define LUA_CSUBSEP		LUA_DIRSEP
  #endif
  
  #if !defined(LUA_LSUBSEP)
  #define LUA_LSUBSEP		LUA_DIRSEP
  #endif
  
  
  /* prefix for open functions in C libraries */
  #define LUA_POF		"luaopen_"
  
  /* separator for open functions in C libraries */
  #define LUA_OFSEP	"_"
  
  
  /*
  ** unique key for table in the registry that keeps handles
  ** for all loaded C libraries
  */
  static const int CLIBS = 0;
  
  #define LIB_FAIL	"open"
  
  
  #define setprogdir(L)           ((void)0)
  
  
  /*
  ** system-dependent functions
  */
  
  /*
  ** unload library 'lib'
  */
  static void lsys_unloadlib (void *lib);
  
  /*
  ** load C library in file 'path'. If 'seeglb', load with all names in
  ** the library global.
  ** Returns the library; in case of error, returns NULL plus an
  ** error string in the stack.
  */
  static void *lsys_load (lua_State *L, const char *path, int seeglb);
  
  /*
  ** Try to find a function named 'sym' in library 'lib'.
  ** Returns the function; in case of error, returns NULL plus an
  ** error string in the stack.
  */
  static lua_CFunction lsys_sym (lua_State *L, void *lib, const char *sym);
  
  
  
  
  #if defined(LUA_USE_DLOPEN)	/* { */
  /*
  ** {========================================================================
  ** This is an implementation of loadlib based on the dlfcn interface.
  ** The dlfcn interface is available in Linux, SunOS, Solaris, IRIX, FreeBSD,
  ** NetBSD, AIX 4.2, HPUX 11, and  probably most other Unix flavors, at least
  ** as an emulation layer on top of native functions.
  ** =========================================================================
  */
  
  #include <dlfcn.h>
  
  /*
  ** Macro to convert pointer-to-void* to pointer-to-function. This cast
  ** is undefined according to ISO C, but POSIX assumes that it works.
  ** (The '__extension__' in gnu compilers is only to avoid warnings.)
  */
  #if defined(__GNUC__)
  #define cast_func(p) (__extension__ (lua_CFunction)(p))
  #else
  #define cast_func(p) ((lua_CFunction)(p))
  #endif
  
  
  static void lsys_unloadlib (void *lib) {
    dlclose(lib);
  }
  
  
  static void *lsys_load (lua_State *L, const char *path, int seeglb) {
    void *lib = dlopen(path, RTLD_NOW | (seeglb ? RTLD_GLOBAL : RTLD_LOCAL));
    if (lib == NULL) lua_pushstring(L, dlerror());
    return lib;
  }
  
  
  static lua_CFunction lsys_sym (lua_State *L, void *lib, const char *sym) {
    lua_CFunction f = cast_func(dlsym(lib, sym));
    if (f == NULL) lua_pushstring(L, dlerror());
    return f;
  }
  
  /* }====================================================== */
  
  
  
  #elif defined(LUA_DL_DLL)	/* }{ */
  /*
  ** {======================================================================
  ** This is an implementation of loadlib for Windows using native functions.
  ** =======================================================================
  */
  
  #include <windows.h>
  
  
  /*
  ** optional flags for LoadLibraryEx
  */
  #if !defined(LUA_LLE_FLAGS)
  #define LUA_LLE_FLAGS	0
  #endif
  
  
  #undef setprogdir
  
  
  /*
  ** Replace in the path (on the top of the stack) any occurrence
  ** of LUA_EXEC_DIR with the executable's path.
  */
  static void setprogdir (lua_State *L) {
    char buff[MAX_PATH + 1];
    char *lb;
    DWORD nsize = sizeof(buff)/sizeof(char);
    DWORD n = GetModuleFileNameA(NULL, buff, nsize);  /* get exec. name */
    if (n == 0 || n == nsize || (lb = strrchr(buff, '\\')) == NULL)
      luaL_error(L, "unable to get ModuleFileName");
    else {
      *lb = '\0';  /* cut name on the last '\\' to get the path */
      luaL_gsub(L, lua_tostring(L, -1), LUA_EXEC_DIR, buff);
      lua_remove(L, -2);  /* remove original string */
    }
  }
  
  
  
  
  static void pusherror (lua_State *L) {
    int error = GetLastError();
    char buffer[128];
    if (FormatMessageA(FORMAT_MESSAGE_IGNORE_INSERTS | FORMAT_MESSAGE_FROM_SYSTEM,
        NULL, error, 0, buffer, sizeof(buffer)/sizeof(char), NULL))
      lua_pushstring(L, buffer);
    else
      lua_pushfstring(L, "system error %d\n", error);
  }
  
  static void lsys_unloadlib (void *lib) {
    FreeLibrary((HMODULE)lib);
  }
  
  
  static void *lsys_load (lua_State *L, const char *path, int seeglb) {
    HMODULE lib = LoadLibraryExA(path, NULL, LUA_LLE_FLAGS);
    (void)(seeglb);  /* not used: symbols are 'global' by default */
    if (lib == NULL) pusherror(L);
    return lib;
  }
  
  
  static lua_CFunction lsys_sym (lua_State *L, void *lib, const char *sym) {
    lua_CFunction f = (lua_CFunction)GetProcAddress((HMODULE)lib, sym);
    if (f == NULL) pusherror(L);
    return f;
  }
  
  /* }====================================================== */
  
  
  #else				/* }{ */
  /*
  ** {======================================================
  ** Fallback for other systems
  ** =======================================================
  */
  
  #undef LIB_FAIL
  #define LIB_FAIL	"absent"
  
  
  #define DLMSG	"dynamic libraries not enabled; check your Lua installation"
  
  
  static void lsys_unloadlib (void *lib) {
    (void)(lib);  /* not used */
  }
  
  
  static void *lsys_load (lua_State *L, const char *path, int seeglb) {
    (void)(path); (void)(seeglb);  /* not used */
    lua_pushliteral(L, DLMSG);
    return NULL;
  }
  
  
  static lua_CFunction lsys_sym (lua_State *L, void *lib, const char *sym) {
    (void)(lib); (void)(sym);  /* not used */
    lua_pushliteral(L, DLMSG);
    return NULL;
  }
  
  /* }====================================================== */
  #endif				/* } */
  
  
  /*
  ** {==================================================================
  ** Set Paths
  ** ===================================================================
  */
  
  /*
  ** LUA_PATH_VAR and LUA_CPATH_VAR are the names of the environment
  ** variables that Lua check to set its paths.
  */
  #if !defined(LUA_PATH_VAR)
  #define LUA_PATH_VAR    "LUA_PATH"
  #endif
  
  #if !defined(LUA_CPATH_VAR)
  #define LUA_CPATH_VAR   "LUA_CPATH"
  #endif
  
  
  #define AUXMARK         "\1"	/* auxiliary mark */
  
  
  /*
  ** return registry.LUA_NOENV as a boolean
  */
  static int noenv (lua_State *L) {
    int b;
    lua_getfield(L, LUA_REGISTRYINDEX, "LUA_NOENV");
    b = lua_toboolean(L, -1);
    lua_pop(L, 1);  /* remove value */
    return b;
  }
  
  
  /*
  ** Set a path
  */
  static void setpath (lua_State *L, const char *fieldname,
                                     const char *envname,
                                     const char *dft) {
    const char *nver = lua_pushfstring(L, "%s%s", envname, LUA_VERSUFFIX);
  #if defined(WINAPI_FAMILY_PARTITION)
    const char *path = NULL;
  #else
    const char *path = getenv(nver);  /* use versioned name */
    if (path == NULL)  /* no environment variable? */
      path = getenv(envname);  /* try unversioned name */
  #endif
    if (path == NULL || noenv(L))  /* no environment variable? */
      lua_pushstring(L, dft);  /* use default */
    else {
      /* replace ";;" by ";AUXMARK;" and then AUXMARK by default path */
      path = luaL_gsub(L, path, LUA_PATH_SEP LUA_PATH_SEP,
                                LUA_PATH_SEP AUXMARK LUA_PATH_SEP);
      luaL_gsub(L, path, AUXMARK, dft);
      lua_remove(L, -2); /* remove result from 1st 'gsub' */
    }
    setprogdir(L);
    lua_setfield(L, -3, fieldname);  /* package[fieldname] = path value */
    lua_pop(L, 1);  /* pop versioned variable name */
  }
  
  /* }================================================================== */
  
  
  /*
  ** return registry.CLIBS[path]
  */
  static void *checkclib (lua_State *L, const char *path) {
    void *plib;
    lua_rawgetp(L, LUA_REGISTRYINDEX, &CLIBS);
    lua_getfield(L, -1, path);
    plib = lua_touserdata(L, -1);  /* plib = CLIBS[path] */
    lua_pop(L, 2);  /* pop CLIBS table and 'plib' */
    return plib;
  }
  
  
  /*
  ** registry.CLIBS[path] = plib        -- for queries
  ** registry.CLIBS[#CLIBS + 1] = plib  -- also keep a list of all libraries
  */
  static void addtoclib (lua_State *L, const char *path, void *plib) {
    lua_rawgetp(L, LUA_REGISTRYINDEX, &CLIBS);
    lua_pushlightuserdata(L, plib);
    lua_pushvalue(L, -1);
    lua_setfield(L, -3, path);  /* CLIBS[path] = plib */
    lua_rawseti(L, -2, luaL_len(L, -2) + 1);  /* CLIBS[#CLIBS + 1] = plib */
    lua_pop(L, 1);  /* pop CLIBS table */
  }
  
  
  /*
  ** __gc tag method for CLIBS table: calls 'lsys_unloadlib' for all lib
  ** handles in list CLIBS
  */
  static int gctm (lua_State *L) {
    lua_Integer n = luaL_len(L, 1);
    for (; n >= 1; n--) {  /* for each handle, in reverse order */
      lua_rawgeti(L, 1, n);  /* get handle CLIBS[n] */
      lsys_unloadlib(lua_touserdata(L, -1));
      lua_pop(L, 1);  /* pop handle */
    }
    return 0;
  }
  
  
  
  /* error codes for 'lookforfunc' */
  #define ERRLIB		1
  #define ERRFUNC		2
  
  /*
  ** Look for a C function named 'sym' in a dynamically loaded library
  ** 'path'.
  ** First, check whether the library is already loaded; if not, try
  ** to load it.
  ** Then, if 'sym' is '*', return true (as library has been loaded).
  ** Otherwise, look for symbol 'sym' in the library and push a
  ** C function with that symbol.
  ** Return 0 and 'true' or a function in the stack; in case of
  ** errors, return an error code and an error message in the stack.
  */
  static int lookforfunc (lua_State *L, const char *path, const char *sym) {
    void *reg = checkclib(L, path);  /* check loaded C libraries */
    if (reg == NULL) {  /* must load library? */
      reg = lsys_load(L, path, *sym == '*');  /* global symbols if 'sym'=='*' */
      if (reg == NULL) return ERRLIB;  /* unable to load library */
      addtoclib(L, path, reg);
    }
    if (*sym == '*') {  /* loading only library (no function)? */
      lua_pushboolean(L, 1);  /* return 'true' */
      return 0;  /* no errors */
    }
    else {
      lua_CFunction f = lsys_sym(L, reg, sym);
      if (f == NULL)
        return ERRFUNC;  /* unable to find function */
      lua_pushcfunction(L, f);  /* else create new function */
      return 0;  /* no errors */
    }
  }
  
  
  static int ll_loadlib (lua_State *L) {
    const char *path = luaL_checkstring(L, 1);
    const char *init = luaL_checkstring(L, 2);
    int stat = lookforfunc(L, path, init);
    if (stat == 0)  /* no errors? */
      return 1;  /* return the loaded function */
    else {  /* error; error message is on stack top */
      lua_pushnil(L);
      lua_insert(L, -2);
      lua_pushstring(L, (stat == ERRLIB) ?  LIB_FAIL : "init");
      return 3;  /* return nil, error message, and where */
    }
  }
  
  
  
  /*
  ** {======================================================
  ** 'require' function
  ** =======================================================
  */
  
  
  static int readable (const char *filename) {
    FILE *f = fopen(filename, "r");  /* try to open file */
    if (f == NULL) return 0;  /* open failed */
    fclose(f);
    return 1;
  }
  
  
  static const char *pushnexttemplate (lua_State *L, const char *path) {
    const char *l;
    while (*path == *LUA_PATH_SEP) path++;  /* skip separators */
    if (*path == '\0') return NULL;  /* no more templates */
    l = strchr(path, *LUA_PATH_SEP);  /* find next separator */
    if (l == NULL) l = path + strlen(path);
    lua_pushlstring(L, path, l - path);  /* template */
    return l;
  }
  
  
  static const char *searchpath (lua_State *L, const char *name,
                                               const char *path,
                                               const char *sep,
                                               const char *dirsep) {
    luaL_Buffer msg;  /* to build error message */
    luaL_buffinit(L, &msg);
    if (*sep != '\0')  /* non-empty separator? */
      name = luaL_gsub(L, name, sep, dirsep);  /* replace it by 'dirsep' */
    while ((path = pushnexttemplate(L, path)) != NULL) {
      const char *filename = luaL_gsub(L, lua_tostring(L, -1),
                                       LUA_PATH_MARK, name);
      lua_remove(L, -2);  /* remove path template */
      if (readable(filename))  /* does file exist and is readable? */
        return filename;  /* return that file name */
      lua_pushfstring(L, "\n\tno file '%s'", filename);
      lua_remove(L, -2);  /* remove file name */
      luaL_addvalue(&msg);  /* concatenate error msg. entry */
    }
    luaL_pushresult(&msg);  /* create error message */
    return NULL;  /* not found */
  }
  
  
  static int ll_searchpath (lua_State *L) {
    const char *f = searchpath(L, luaL_checkstring(L, 1),
                                  luaL_checkstring(L, 2),
                                  luaL_optstring(L, 3, "."),
                                  luaL_optstring(L, 4, LUA_DIRSEP));
    if (f != NULL) return 1;
    else {  /* error message is on top of the stack */
      lua_pushnil(L);
      lua_insert(L, -2);
      return 2;  /* return nil + error message */
    }
  }
  
  
  static const char *findfile (lua_State *L, const char *name,
                                             const char *pname,
                                             const char *dirsep) {
    const char *path;
    lua_getfield(L, lua_upvalueindex(1), pname);
    path = lua_tostring(L, -1);
    if (path == NULL)
      luaL_error(L, "'package.%s' must be a string", pname);
    return searchpath(L, name, path, ".", dirsep);
  }
  
  
  static int checkload (lua_State *L, int stat, const char *filename) {
    if (stat) {  /* module loaded successfully? */
      lua_pushstring(L, filename);  /* will be 2nd argument to module */
      return 2;  /* return open function and file name */
    }
    else
      return luaL_error(L, "error loading module '%s' from file '%s':\n\t%s",
                            lua_tostring(L, 1), filename, lua_tostring(L, -1));
  }
  
  
  static int searcher_Lua (lua_State *L) {
    const char *filename;
    const char *name = luaL_checkstring(L, 1);
    filename = findfile(L, name, "path", LUA_LSUBSEP);
    if (filename == NULL) return 1;  /* module not found in this path */
    return checkload(L, (luaL_loadfile(L, filename) == LUA_OK), filename);
  }
  
  
  /*
  ** Try to find a load function for module 'modname' at file 'filename'.
  ** First, change '.' to '_' in 'modname'; then, if 'modname' has
  ** the form X-Y (that is, it has an "ignore mark"), build a function
  ** name "luaopen_X" and look for it. (For compatibility, if that
  ** fails, it also tries "luaopen_Y".) If there is no ignore mark,
  ** look for a function named "luaopen_modname".
  */
  static int loadfunc (lua_State *L, const char *filename, const char *modname) {
    const char *openfunc;
    const char *mark;
    modname = luaL_gsub(L, modname, ".", LUA_OFSEP);
    mark = strchr(modname, *LUA_IGMARK);
    if (mark) {
      int stat;
      openfunc = lua_pushlstring(L, modname, mark - modname);
      openfunc = lua_pushfstring(L, LUA_POF"%s", openfunc);
      stat = lookforfunc(L, filename, openfunc);
      if (stat != ERRFUNC) return stat;
      modname = mark + 1;  /* else go ahead and try old-style name */
    }
    openfunc = lua_pushfstring(L, LUA_POF"%s", modname);
    return lookforfunc(L, filename, openfunc);
  }
  
  
  static int searcher_C (lua_State *L) {
    const char *name = luaL_checkstring(L, 1);
    const char *filename = findfile(L, name, "cpath", LUA_CSUBSEP);
    if (filename == NULL) return 1;  /* module not found in this path */
    return checkload(L, (loadfunc(L, filename, name) == 0), filename);
  }
  
  
  static int searcher_Croot (lua_State *L) {
    const char *filename;
    const char *name = luaL_checkstring(L, 1);
    const char *p = strchr(name, '.');
    int stat;
    if (p == NULL) return 0;  /* is root */
    lua_pushlstring(L, name, p - name);
    filename = findfile(L, lua_tostring(L, -1), "cpath", LUA_CSUBSEP);
    if (filename == NULL) return 1;  /* root not found */
    if ((stat = loadfunc(L, filename, name)) != 0) {
      if (stat != ERRFUNC)
        return checkload(L, 0, filename);  /* real error */
      else {  /* open function not found */
        lua_pushfstring(L, "\n\tno module '%s' in file '%s'", name, filename);
        return 1;
      }
    }
    lua_pushstring(L, filename);  /* will be 2nd argument to module */
    return 2;
  }
  
  
  static int searcher_preload (lua_State *L) {
    const char *name = luaL_checkstring(L, 1);
    lua_getfield(L, LUA_REGISTRYINDEX, LUA_PRELOAD_TABLE);
    if (lua_getfield(L, -1, name) == LUA_TNIL)  /* not found? */
      lua_pushfstring(L, "\n\tno field package.preload['%s']", name);
    return 1;
  }
  
  
  static void findloader (lua_State *L, const char *name) {
    int i;
    luaL_Buffer msg;  /* to build error message */
    luaL_buffinit(L, &msg);
    /* push 'package.searchers' to index 3 in the stack */
    if (lua_getfield(L, lua_upvalueindex(1), "searchers") != LUA_TTABLE)
      luaL_error(L, "'package.searchers' must be a table");
    /*  iterate over available searchers to find a loader */
    for (i = 1; ; i++) {
      if (lua_rawgeti(L, 3, i) == LUA_TNIL) {  /* no more searchers? */
        lua_pop(L, 1);  /* remove nil */
        luaL_pushresult(&msg);  /* create error message */
        luaL_error(L, "module '%s' not found:%s", name, lua_tostring(L, -1));
      }
      lua_pushstring(L, name);
      lua_call(L, 1, 2);  /* call it */
      if (lua_isfunction(L, -2))  /* did it find a loader? */
        return;  /* module loader found */
      else if (lua_isstring(L, -2)) {  /* searcher returned error message? */
        lua_pop(L, 1);  /* remove extra return */
        luaL_addvalue(&msg);  /* concatenate error message */
      }
      else
        lua_pop(L, 2);  /* remove both returns */
    }
  }
  
  
  static int ll_require (lua_State *L) {
    const char *name = luaL_checkstring(L, 1);
    lua_settop(L, 1);  /* LOADED table will be at index 2 */
    lua_getfield(L, LUA_REGISTRYINDEX, LUA_LOADED_TABLE);
    lua_getfield(L, 2, name);  /* LOADED[name] */
    if (lua_toboolean(L, -1))  /* is it there? */
      return 1;  /* package is already loaded */
    /* else must load package */
    lua_pop(L, 1);  /* remove 'getfield' result */
    findloader(L, name);
    lua_pushstring(L, name);  /* pass name as argument to module loader */
    lua_insert(L, -2);  /* name is 1st argument (before search data) */
    lua_call(L, 2, 1);  /* run loader to load module */
    if (!lua_isnil(L, -1))  /* non-nil return? */
      lua_setfield(L, 2, name);  /* LOADED[name] = returned value */
    if (lua_getfield(L, 2, name) == LUA_TNIL) {   /* module set no value? */
      lua_pushboolean(L, 1);  /* use true as result */
      lua_pushvalue(L, -1);  /* extra copy to be returned */
      lua_setfield(L, 2, name);  /* LOADED[name] = true */
    }
    return 1;
  }
  
  /* }====================================================== */
  
  
  
  /*
  ** {======================================================
  ** 'module' function
  ** =======================================================
  */
  #if defined(LUA_COMPAT_MODULE)
  
  /*
  ** changes the environment variable of calling function
  */
  static void set_env (lua_State *L) {
    lua_Debug ar;
    if (lua_getstack(L, 1, &ar) == 0 ||
        lua_getinfo(L, "f", &ar) == 0 ||  /* get calling function */
        lua_iscfunction(L, -1))
      luaL_error(L, "'module' not called from a Lua function");
    lua_pushvalue(L, -2);  /* copy new environment table to top */
    lua_setupvalue(L, -2, 1);
    lua_pop(L, 1);  /* remove function */
  }
  
  
  static void dooptions (lua_State *L, int n) {
    int i;
    for (i = 2; i <= n; i++) {
      if (lua_isfunction(L, i)) {  /* avoid 'calling' extra info. */
        lua_pushvalue(L, i);  /* get option (a function) */
        lua_pushvalue(L, -2);  /* module */
        lua_call(L, 1, 0);
      }
    }
  }
  
  
  static void modinit (lua_State *L, const char *modname) {
    const char *dot;
    lua_pushvalue(L, -1);
    lua_setfield(L, -2, "_M");  /* module._M = module */
    lua_pushstring(L, modname);
    lua_setfield(L, -2, "_NAME");
    dot = strrchr(modname, '.');  /* look for last dot in module name */
    if (dot == NULL) dot = modname;
    else dot++;
    /* set _PACKAGE as package name (full module name minus last part) */
    lua_pushlstring(L, modname, dot - modname);
    lua_setfield(L, -2, "_PACKAGE");
  }
  
  
  static int ll_module (lua_State *L) {
    const char *modname = luaL_checkstring(L, 1);
    int lastarg = lua_gettop(L);  /* last parameter */
    luaL_pushmodule(L, modname, 1);  /* get/create module table */
    /* check whether table already has a _NAME field */
    if (lua_getfield(L, -1, "_NAME") != LUA_TNIL)
      lua_pop(L, 1);  /* table is an initialized module */
    else {  /* no; initialize it */
      lua_pop(L, 1);
      modinit(L, modname);
    }
    lua_pushvalue(L, -1);
    set_env(L);
    dooptions(L, lastarg);
    return 1;
  }
  
  
  static int ll_seeall (lua_State *L) {
    luaL_checktype(L, 1, LUA_TTABLE);
    if (!lua_getmetatable(L, 1)) {
      lua_createtable(L, 0, 1); /* create new metatable */
      lua_pushvalue(L, -1);
      lua_setmetatable(L, 1);
    }
    lua_pushglobaltable(L);
    lua_setfield(L, -2, "__index");  /* mt.__index = _G */
    return 0;
  }
  
  #endif
  /* }====================================================== */
  
  
  
  static const luaL_Reg pk_funcs[] = {
    {"loadlib", ll_loadlib},
    {"searchpath", ll_searchpath},
  #if defined(LUA_COMPAT_MODULE)
    {"seeall", ll_seeall},
  #endif
    /* placeholders */
    {"preload", NULL},
    {"cpath", NULL},
    {"path", NULL},
    {"searchers", NULL},
    {"loaded", NULL},
    {NULL, NULL}
  };
  
  
  static const luaL_Reg ll_funcs[] = {
  #if defined(LUA_COMPAT_MODULE)
    {"module", ll_module},
  #endif
    {"require", ll_require},
    {NULL, NULL}
  };
  
  
  static void createsearcherstable (lua_State *L) {
    static const lua_CFunction searchers[] =
      {searcher_preload, searcher_Lua, searcher_C, searcher_Croot, NULL};
    int i;
    /* create 'searchers' table */
    lua_createtable(L, sizeof(searchers)/sizeof(searchers[0]) - 1, 0);
    /* fill it with predefined searchers */
    for (i=0; searchers[i] != NULL; i++) {
      lua_pushvalue(L, -2);  /* set 'package' as upvalue for all searchers */
      lua_pushcclosure(L, searchers[i], 1);
      lua_rawseti(L, -2, i+1);
    }
  #if defined(LUA_COMPAT_LOADERS)
    lua_pushvalue(L, -1);  /* make a copy of 'searchers' table */
    lua_setfield(L, -3, "loaders");  /* put it in field 'loaders' */
  #endif
    lua_setfield(L, -2, "searchers");  /* put it in field 'searchers' */
  }
  
  
  /*
  ** create table CLIBS to keep track of loaded C libraries,
  ** setting a finalizer to close all libraries when closing state.
  */
  static void createclibstable (lua_State *L) {
    lua_newtable(L);  /* create CLIBS table */
    lua_createtable(L, 0, 1);  /* create metatable for CLIBS */
    lua_pushcfunction(L, gctm);
    lua_setfield(L, -2, "__gc");  /* set finalizer for CLIBS table */
    lua_setmetatable(L, -2);
    lua_rawsetp(L, LUA_REGISTRYINDEX, &CLIBS);  /* set CLIBS table in registry */
  }
  
  
  LUAMOD_API int luaopen_package (lua_State *L) {
    createclibstable(L);
    luaL_newlib(L, pk_funcs);  /* create 'package' table */
    createsearcherstable(L);
    /* set paths */
    setpath(L, "path", LUA_PATH_VAR, LUA_PATH_DEFAULT);
    setpath(L, "cpath", LUA_CPATH_VAR, LUA_CPATH_DEFAULT);
    /* store config information */
    lua_pushliteral(L, LUA_DIRSEP "\n" LUA_PATH_SEP "\n" LUA_PATH_MARK "\n"
                       LUA_EXEC_DIR "\n" LUA_IGMARK "\n");
    lua_setfield(L, -2, "config");
    /* set field 'loaded' */
    luaL_getsubtable(L, LUA_REGISTRYINDEX, LUA_LOADED_TABLE);
    lua_setfield(L, -2, "loaded");
    /* set field 'preload' */
    luaL_getsubtable(L, LUA_REGISTRYINDEX, LUA_PRELOAD_TABLE);
    lua_setfield(L, -2, "preload");
    lua_pushglobaltable(L);
    lua_pushvalue(L, -2);  /* set 'package' as upvalue for next lib */
    luaL_setfuncs(L, ll_funcs, 1);  /* open lib into global table */
    lua_pop(L, 1);  /* pop global table */
    return 1;  /* return 'package' table */
  }
  
  