Re: <new> in stdafx.h and std::nothrow causes export from EXE
"Pieter" wrote:
We noticed a strange problem with VC8 SP1 that does not
happen with VC 7.1 SP1.
If you include <new> in stdafx.h, and you use
new(std::nothrow) the release EXE will export this
function:
class std::_Init_locks & std::_Init_locks::operator=(class
std::_Init_locks const &)
[...]
Any ideas how to prevent or fix this?
First of all, why do you consider it to be a problem? This
benign export doesn't have any impact on anything and
program runs correctly with or without it.
I'm not 100% sure as of why this exports appears. After
playing a little bit with test project I noticed following:
1. `_Init_locks' class doesn't define operator=, so it's
generated by compiler. `_Init_locks::operator=' is exported
because whole class is exported by default (in case you
compile with /MD switch).
2. `_Init_locks::operator=' function comes from
"msvcprt.lib" (DUMPBIN /exports msvcprt.lib), however it
exported from "msvcp80.dll" like this:
??4_Init_locks@std@@QAEAAV01@ABV01@@Z =
??4_Num_float_base@std@@QAEAAU01@ABU01@@Z
where "??4_Num_float_base@std@@QAEAAU01@ABU01@@Z" is
public: struct std::_Num_float_base & __thiscall
std::_Num_float_base::operator=(struct std::_Num_float_base
const &)
Probably this is the source of the problem.
3. Also, linker reorders some of functions even if /ORDER
switch isn't specified. If you enable verbose linker output,
then you'll find that following processing occurs:
....
External code objects not listed in the /ORDER file:
...
??4_Init_locks@std@@QAEAAV01@ABV01@@Z ;
msvcprt.lib(nothrow.obj)
...
So, it seems that `_Init_locks::operator=' is in predefined
linker order list (whatever it means). Considering all this,
I think that exporting `_Init_locks::operator=' from EXE is
some harmless linker quirk. Call it a bug, if you like. I
tried to reproduce it with simple EXE/DLL project, however
without success.
While searching for solution I noticed that static
multithread Standard C++ Library (libcpmt.lib) doesn't
contain `_Init_locks::operator=' among its symbols. So, by
adding `_STATIC_CPPLIB' to project's preprocessor
definitions you can eliminate `_Init_locks::operator='
export from EXE. CRT code still will be used from dynamic
library, but Standard C++ Library code will be linked
statically.
HTH
Alex