Question

Please tell me what difference between pthread versions: VC2, VCE2 and VSE2? How to choose which of them I must use with Visual C++ Express 2010 for Mongoose webserver library?

Thank you!!!

Answer 1

• VCE – MSVC dll with C++ exception handling
• VSE – MSVC dll with structured exception handling
• VC – MSVC dll with C cleanup code

Which one you’d want to use with VC++ Express 2010 depends on how you want pthread clean up to be handled. If you’re linking this to the Mongoose webserver (which I’m not familiar with), I think you’ll want to use the exception handling model as that code is compiled with.

The pthreads Win32 library goes into a fair bit of detail:

Library naming

Because the library is being built
using various exception handling
schemes and compilers – and because
the library may not work reliably if
these are mixed in an application,
each different version of the library
has it’s own name.

Note 1: the incompatibility is really
between EH implementations of the
different compilers. It should be
possible to use the standard C version
from either compiler with C++
applications built with a different
compiler. If you use an EH version of
the library, then you must use the
same compiler for the application.
This is another complication and
dependency that can be avoided by
using only the standard C library
version.

Note 2: if you use a standard C
pthread*.dll with a C++ application,
then any functions that you define
that are intended to be called via
pthread_cleanup_push() must be
__cdecl.

Note 3: the intention was to also name
either the VC or GC version (it should
be arbitrary) as pthread.dll,
including pthread.lib and libpthread.a
as appropriate. This is no longer
likely to happen.

Note 4: the compatibility number was
added so that applications can
differentiate between binary
incompatible versions of the libs and
dlls.

In general: pthread[VG]{SE,CE,C}c.dll
pthread[VG]{SE,CE,C}c.lib

where: [VG] indicates the compiler
V – MS VC, or G – GNU C

{SE,CE,C} indicates the exception
handling scheme SE – Structured EH,
or CE – C++ EH, or C – no exceptions
– uses setjmp/longjmp

c – DLL compatibility number
indicating ABI and API
compatibility with applications built against
any snapshot with the same compatibility number.
See ‘Version numbering’ below.

The name may also be suffixed by a ‘d’
to indicate a debugging version of the
library. E.g. pthreadVC2d.lib.
Debugging versions contain additional
information for debugging (symbols
etc) and are often not optimised in
any way (compiled with optimisation
turned off).

For example:
pthreadVSE.dll (MSVC/SEH)
pthreadGCE.dll (GNUC/C++ EH)
pthreadGC.dll (GNUC/not dependent on
exceptions) pthreadVC1.dll (MSVC/not
dependent on exceptions – not binary
compatible with pthreadVC.dll)
pthreadVC2.dll (MSVC/not dependent on
exceptions – not binary compatible
with pthreadVC1.dll or pthreadVC.dll)

The GNU library archive file names
have correspondingly changed to:

libpthreadGCEc.a libpthreadGCc.a

If you want to see what the differences are for each of these clean up models, search for “__CLEANUP” in the pthreads Win32 source (there are only a few places where the different clean up models come into play).