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This code

import bindbc.lua;

void main()
{
	LuaSupport lua = loadLua();
	auto L = luaL_newstate();
	luaL_requiref(L, "_G", luaopen_base, 0);
	lua_pop(L, 1);
	lua_close(L);
}

generates a compile-time error like this:

source/app.d(32,15): Error: function pointer `luaL_requiref(lua_State* L, const(char)* modname, int function(lua_State* L) nothrow openf, int glb)` is not callable using argument types `(lua_State*, string, extern (C) int function(lua_State* L) nothrow @nogc, int)`
source/app.d(32,15):        cannot pass argument `luaopen_base` of type `extern (C) int function(lua_State* L) nothrow @nogc` to parameter `int function(lua_State* L) nothrow openf`
/usr/bin/dmd failed with exit code 1.

I attempted to hack this by fiddling with @nogc at declarations, but it caused even more problems. I believe some better investigation is required

Is it possible to support the latest Lua version such as 5.4.2?

• Consolidate the 4 separate sets of bindings into 1, using conditional compilation.
• Use BindBC-Common ~>0.1.1.
• Consider renaming some symbols.
• Bind older Lua versions, or maybe even LuaJIT?

the callback types like lua_CFunction are currently declared without an extern() so they default to extern(D), but the calling convention for those isn't compatible with extern(C) in all cases:

• according to issue 20204, extern(D) functions are passed their arguments in reverse order compared to extern(C) (this doesn't affect the common lua_CFunction since it has just 1 parameter)
• windows/x86 has its D calling convention documented here, which is supposedly different enough from the C one that it had to be specifically documented

one of the types this affects is custom allocator functions since they have 4 parameters:

/+ dub.sdl:
dependency "bindbc-lua" version="~>0.4.1"
subConfigurations "bindbc-lua" "static"  platform="posix"
versions "BindLua_Static" "LUA_54"       platform="posix"
libs "lua5.4"                            platform="posix"
+/
import core.stdc.stdlib;
import std.exception;
import std.stdio;
import bindbc.lua;

// https://www.lua.org/manual/5.4/manual.html#lua_Alloc
extern (C) // <-- change to extern(D) and it breaks
void* myalloc(void* ud, void* ptr, size_t osize, size_t nsize) nothrow
{
	writefln("ud=%s ptr=%s osize=%s nsize=%s", ud, ptr, osize, nsize).assumeWontThrow;
	if (nsize == 0)
		{ free(ptr); return null; }
	else
		return realloc(ptr, nsize);
}

// lua_Alloc with D calling convention (same as bindbc-lua)
alias lua_Alloc_D = extern (D) void* function(void* ud, void* ptr, size_t osize, size_t nsize) nothrow;

void main()
{
	lua_State* L = luaL_newstate();
	lua_setallocf(L, cast(lua_Alloc_D)&myalloc, null);
	luaL_openlibs(L);
	if (LUA_OK != luaL_dostring(L, `
	print("hello world")
	`)) lua_error(L);
	lua_close(L);
}

with extern(C) on the allocator function, it works normally but if changed to extern(D), it prints bogus values and crashes (tested on linux with dmd, 64-bit and 32-bit)

in general, any function that's going to be called by C code should have extern(C) to work correctly

While according to official specifications ( https://www.lua.org/manual/5.4/manual.html#lua_Reader ) it should be a size_t*, but in this library it's not a pointer.

https://github.com/BindBC/bindbc-lua/blob/master/source/bindbc/lua/v54/types.d#L124

https://github.com/BindBC/bindbc-lua/blob/master/source/bindbc/lua/v53/types.d#L85

Didn't check any of the even older ones.

extern (D) is not the correct calling convention. This causes segfaults.

I get this error whenever I'm trying to using lua 5.4 with bindbc-lua:

../../../.dub/packages/bindbc-lua-0.4.0/bindbc-lua/source/bindbc/lua/v54/package.d(323,9): Error: return expression expected

Although I think it's something on my end, as it seems there is a return in the source code, but I'm not sure?

lua_getstack should be declared as lua_getstack(lua_State *L, int level, lua_Debug *ar) but is currently missing the level parameter in the static bindings for Lua 5.1.

Looks like the 5.3 bindings just arent done yet, but it was a pain to figure out why it wasnt finding my shared library, so this issue can just serve as a warning

• In source/bindbc/lua/v53/package.d, line 140
• lua_checklong is declared twice — both with the wrong parameters
• lua_optlong is missing

Trivia

• DMD doesn't catch this error
• LDC2 does