Re: [Mingw-w64-public] [Mingw-users] mingw64: linking fails, underscore / calling convention?

[JonY <jo...@us...>]

On 4/23/2011 15:34, fk...@go... wrote:
> Hi,
> 
> My 32 bit mingw cross compiler works, but the 64 version
> fails when linking system libraries.
> 
> I've set up a x86_64-pc-mingw32 64 bit cross compiler (under
> gentoo linux with paludis packet manager).
> 
> I can compile 64 bit code, however, linking fails:
> 
> /usr/lib/gcc/x86_64-pc-mingw32/4.5.2/../../../../x86_64-pc-mingw32/lib/dllcrt2.o:crtdll.c:(.text+0xb):
> undefined reference to `malloc'
> (... and a lot more)
> 
> When I lookup dllcrt2.o from my existing 32 bit cross
> compiler, then 'malloc' has an underscore, but the 64 bit
> version of dllcrt2.o does NOT have one.
> 
> I have read that some calling convention has changed.
> However, what are the steps to solve this then?
> 
> FYI: I am using mingw64-runtime-20101003,
> binutils-2.21.51.0.8, gcc-4.5.2.
> 
>  Felix
> 
> 

-- Adding to mingw-w64 public list --

Hi,

The underscore part is correct, win64 symbols do not have underscore
prefixes like win32 symbols.

Yes, call convention changed, GCC 4.5.0, 4.4.x and earlier will use
underscores regardless of win32/win64 target. It was a design decision
mistake. GCC 4.5.1 and later including the 4.6.x series will use
underscore prefix only for win32.

Btw, please use x86_64-w64-mingw32 instead of x86_64-pc-mingw32, the
latter is only used for compatibility, I'd admit there isn't much
compatibility with 32bit mingw.