i386 __attribute__((fastcall))

[namtsui]

on i386 32-bit openbsd with luabridge https://github.com/vinniefalco/LuaBridge/commit/9092ace9615d14e3f5926f2e8a3b612ddc6c8efa I get a compilation error when trying to addFunction with a function that uses attribute fastcall. Removing fastcall allows the program to compile.

relevant section of Namespace.h:

   1280     //----------------------------------------------------------------------------
   1281     /**
   1282         Add or replace a free function.
   1283     */
   1284     template<class ReturnType, class... Params>
   1285     Namespace& addFunction(char const* name, ReturnType (*fp)(Params...))
   1286     {

reproducible example:

// c++ -I/usr/local/include -I/usr/local/include/lua-5.3 /usr/local/lib/liblua5.3.so.5.3 luabridge.cpp

#include <vector>
#include <cmath>
#include <iostream>
#include <lua.hpp>
#include <LuaBridge/LuaBridge.h>

using std::vector;
using std::cout;
using std::endl;

//basic types
typedef int8_t  s8;
typedef int16_t s16;
typedef int32_t s32;
typedef int64_t s64;

typedef uint8_t  u8;
typedef uint16_t u16;
typedef uint32_t u32;
typedef uint64_t u64;

typedef float f32;
typedef double f64;

#define DYNACALL __attribute__((fastcall))

u8 DYNACALL _vmem_readt_8(u32 addr)
{
        return 23;
}

using namespace luabridge;

int main()
{
        static lua_State *L;

        getGlobalNamespace(L)
                .beginNamespace("memory")
                        .addFunction("read8", _vmem_readt_8)
                .endNamespace();
        return 0;
}

$ c++ -I/usr/local/include -I/usr/local/include/lua-5.3 /usr/local/lib/liblua5.3.so.5.3 luabridge.cpp         
luabridge.cpp:42:5: error: no matching member function for call to 'addFunction'
                        .addFunction("read8", _vmem_readt_8)
                        ~^~~~~~~~~~~
/usr/local/include/LuaBridge/detail/Namespace.h:1326:16: note: candidate function not viable: no known conversion from 'DYNACALL u8 (u32) __attribute__((fastcall))' (aka 'unsigned char (unsigned int) __attribute__((fastcall))') to 'int (*const)(lua_State *)' for 2nd argument
    Namespace& addFunction(char const* name, int (*const fp)(lua_State*))
               ^
/usr/local/include/LuaBridge/detail/Namespace.h:1263:16: note: candidate template ignored: could not match 'function<type-parameter-0-0 (type-parameter-0-1...)>' against 'unsigned char (*)(unsigned int) __attribute__((fastcall))'
    Namespace& addFunction(char const* name, std::function<ReturnType(Params...)> function)
               ^
/usr/local/include/LuaBridge/detail/Namespace.h:1285:16: note: candidate template ignored: deduced type 'unsigned char (*)(unsigned int)' of 2nd parameter does not match adjusted type 'DYNACALL u8 (*)(u32) __attribute__((fastcall))' (aka 'unsigned char (*)(unsigned int) __attribute__((fastcall))') of argument [with ReturnType = unsigned char, Params = <unsigned int>]
    Namespace& addFunction(char const* name, ReturnType (*fp)(Params...))
               ^
1 error generated.

[dmitry-t]

Sorry for a late response, do you have a solution now?