Re: problem using static libcurl

From:

"Scott McPhillips [MVP]" <org-dot-mvps-at-scottmcp>

Newsgroups:

microsoft.public.vc.language

Date:

Wed, 01 Aug 2007 08:41:56 -0400

Message-ID:

<3PednespRqYx4i3bnZ2dnUVZ_qCgnZ2d@comcast.com>

Ucayaly Fish wrote:

Hi,
I'm trying to use libcurl in a legacy Win32 server based on
CComModule. It was first created using VC 6 and is build currently
using VC 7.1 without service pack. The service gets a batch of
requests from database, creates a few CWinThread objects and
distributes requests to them. Each thread processes requests using
HTTPS connections to request specific url.
If I use libcurl in a dll, everything just works fine. On the other
hand, if I try to use static libcurl library, I get assets from free
function called from inside libcurl (_CrtIsValidHeapPointer does not
validate the pointer). I've made all possible checks make sure that
both libcurl and server app are build with the same runtime and other
project settings.
Any suggestions? I wouldn't like to leave such a dangerous bug behind
without clear explanation.

TIA

This sounds like what is typically caused by using static linking to the
C runtime library. If both your server and your lib link statically to
the runtime lib then you get two copies of the runtime lib, and so two
heaps. The libs don't recognize pointers to each other's heaps.

If all modules use the DLL version of the runtime lib this problem goes
away: all modules share one instance of the lib. See /MD and /MDd
compiler options.

--
Scott McPhillips [MVP VC++]