Re: Strange linker errors (LNK2005) in Release build only .... why ??

Hello Nanda,

Thanks for the reply. Well I tried that route but looks like a DLL still
needs the DLLStartupMain() which is defined in the libc/libcmt/dll versions.
So looks I cannot get around having to link to the dll version of libc if
I'm making a dll - seems odd to me, since I'm a Unix guy trying to massage
some code in Windows land (and hitting every roadblock on the way!!).

Have you built DLLs without linking/referring to some form of libc ??

Thanks,
Krishnan
"Nanda" <nandagopal.seshagiri@xxxxxxxxx> wrote in message
news:ewr6e7o5FHA.4012@xxxxxxxxxxxxxxxxxxxxxxx
> There is way, "dont use c-runtime library". If the number of trivial CRT
> function u need are less then it is quite possible, as sometimes there are
> typical win32 wrappers for certain functions.
>
> nanda
>
> "Krishnan R.S." <rskrishnan@xxxxxxxxxxx> wrote in message
> news:eCwmjEi5FHA.3976@xxxxxxxxxxxxxxxxxxxxxxx
>> So is there no way to override/replace malloc/free with my implementation
> in
>> a dll ??
>>
>> Thanks,
>> Krishnan
>>
>> "Nanda" <nandagopal.seshagiri@xxxxxxxxx> wrote in message
>> news:eTkBJbe5FHA.884@xxxxxxxxxxxxxxxxxxxxxxx
>> > Hi,
>> >
>> > U are seeing this problem only in release build because, in debug, the
>> free
>> > and malloc are exported or used as _free_dbg and _malloc_dbg from
>> > msvcrt70d.dll, where as in release they are exported as free and
>> > malloc.
>> >
>> > nanda
>> >
>> > "Krishnan R.S." <rskrishnan@xxxxxxxxxxx> wrote in message
>> > news:%23$H7jjV5FHA.3636@xxxxxxxxxxxxxxxxxxxxxxx
>> > > Hello All,
>> > >
>> > > First off I'd like to say I am not mixing the static and dll
>> versions
>> > of
>> > > the runtime in my dll - I use /MDd for the debug and /MD for the
> release
>> > > versions of DLMAlloc.dll. I tried all sorts of options for the linker
>> but
>> > it
>> > > seems adamantly stuck on not building the release version alone!
>> > >
>> > > I've got a project where I'm trying to use dlmalloc.c instead of
> the
>> > > usual vc7 malloc() - i.e. I want to build a drop in replacement for
> the
>> > > default vc7 malloc() allocator. To use this allocator in all my dlls
>> > > I
>> > need
>> > > to build this as a separate dll - called say DLMalloc.dll.
>> > >
>> > > I've attached a zip file containing the source + the vcproj files
> if
>> > you
>> > > are interested ...
>> > >
>> > > I have a project in MSVC 7.1 setup to build a dll (not a static
>> lib) -
>> > > all seems fine in the debug build. I am able to build my
>> > > DLMalloc.dll,
>> and
>> > > DLMalloc.lib - and use it to build my app, successfuly links and
>> > > works
>> > too!
>> > >
>> > > The problem comes when I try to build a release build of
>> > > DLMalloc.dll/DLMalloc.lib. The compile goes fine - but I get a linker
>> > error.
>> > > The linker thinks that _free and _malloc are defined multiple times -
>> why
>> > ??
>> > >
>> > > Why do I get this symbol conflict only on release builds ? I
> suspect
>> > that
>> > > the MSVCR71.dll has internally linked to the malloc/free
> implementations
>> > > available in the runtime - is that possible ?? If so why does it
>> > > work
>> on
>> > > the debug build ??
>> > >
>> > > I tried switching to incremental linking on the release build
> (using
>> > > /OPT:NOREF /OPT:NOICF with /INCREMENTAL) but no luck whatsoever.
>> > > I tried looking at the verbose output of the linker - and it
>> > > seems
>> > like
>> > > the reference to free is from crtdll.obj - see snippet below.
>> > >
>> > > ---snippet from the verbose linker output ---
>> > > Found __imp__free
>> > > Referenced in MSVCRT.lib(crtdll.obj)
>> > > Loaded MSVCRT.lib(MSVCR71.dll)
>> > > MSVCRT.lib(MSVCR71.dll) : error LNK2005: _free already defined in
>> > malloc.obj
>> > > --- end snippet ----
>> > >
>> > > I may very well be on the wrong track with my diagnosis ....
>> > > I'd appreciate any help you can give me on this issue.
>> > >
>> > > Thanks,
>> > > Krishnan
>> > >
>> > >
>> > >
>> > >
>> > >
>> >
>> >
>>
>>
>
>


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