A loadall.dll file prevents other DLLs from loading

["Francois Retief" <fgretief@...>]

Hello all,

I would like to confirm an issue with Lua v5.1.3 loader_C function (in
loadlib.c).

We have two DLLs.  One called loadall.dll and another called MyCompany.dll.
Both is located in the same directory as our lua executable
(W:\work\lua5.1.exe).  The second DLL has a function called
luaopen_MyCompany_SubSystem_UnitA that is the entry point into our module.

We try to load the UnitA module into Lua, but instead get this error:

> require "MyCompany.SubSystem.UnitA"
error loading module 'MyCompany.SubSystem.UnitA' from file
'W:\work\loadall.dll':
        The specified procedure could not be found.

It seems loadall.dll prevents Lua from finding our module. The 4th searcher
('all-in-one' loader) is never executed.

The relevant function from the Lua 5.1.3 sources (see below) show the
problem.  In loader_C, line 409 will throw an error on the first DLL that it
finds that does not have the correct luaopen_ function. This error stops all
other loaders after this one. This is not what we expected to happen
(according to the docs).

401
402 static int loader_C (lua_State *L) {
403   const char *funcname;
404   const char *name = luaL_checkstring(L, 1);
405   const char *filename = findfile(L, name, "cpath");
406   if (filename == NULL) return 1;  /* library not found in this path */
407   funcname = mkfuncname(L, name);
408   if (ll_loadfunc(L, filename, funcname) != 0)
409     loaderror(L, filename);                         // <-- issue
410   return 1;  /* library loaded successfully */
411 }
412
413
414 static int loader_Croot (lua_State *L) {
415   const char *funcname;
416   const char *filename;
417   const char *name = luaL_checkstring(L, 1);
418   const char *p = strchr(name, '.');
419   int stat;
420   if (p == NULL) return 0;  /* is root */
421   lua_pushlstring(L, name, p - name);
422   filename = findfile(L, lua_tostring(L, -1), "cpath");
423   if (filename == NULL) return 1;  /* root not found */
424   funcname = mkfuncname(L, name);
425   if ((stat = ll_loadfunc(L, filename, funcname)) != 0) {
426     if (stat != ERRFUNC) loaderror(L, filename);  /* real error */
427     lua_pushfstring(L, "\n\tno module " LUA_QS " in file " LUA_QS,
428                        name, filename);
429     return 1;  /* function not found */
430   }
431   return 1;
432 }
433

A solution to this issue would be to replace line 409 with the same code from
lines 426 to 429 in loader_Croot.

Can somebody please confirm that this is an issue in Lua 5.1.3? Or is it
expected behaviour?

Cheers
  Francois
________________________________________
Francois Retief
Sun Space & Information Systems (Pty) Ltd.
Stellenbosch, South Africa
www.sunspace.co.za
+27 21 880 8100
+27 21 880 1703 (fax)



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